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My problem with SLI and Crossfire

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July 1, 2007 2:26:56 AM

Come on guys - If I have a low to mid range graphics card, and I wanted to really increase my playing experience, I would definitely consider an SLI or Crossfire setup. What angers me is that it doesn't double your performance. 2 7600's or 2 X1650's should rip through any game right now. But the benchmarks I've seen tell a different story. SLI wasn't made for low to mid range video cards, even though they've enabled it. It was meant to lure those who are willing to pay for high end video cards, into purchasing 2 with the assurance that you would get 2x the performance. But SLI/Crossfire cripples what 2 cards should actually be able to do. Any way you put it, the 2 are supposed to equally divide the work between them. This might be simplifying the process, but I've read enough on the subjects. Why then doesn't it work a lot better than it does? SLI/Crossfire for games - 2 or 4 PCIx16/PCIx8 slots on motherboards - pure marketing hype created to get your money. Now I do like the idea of one card processing certain aspects of the graphics, i.e. one handling physics, and perhaps T&L while the other did something else. In either case, the full potential of the card isn't realized. No disrespect to any of you with multiple cards in your machines. Just an observation.

More about : problem sli crossfire

a c 271 U Graphics card
July 1, 2007 3:06:36 AM

Right, first off the term 'Sli' has been around for a long time 1996 in fact and back then it stood for Scan Line Interweave where as now it means Scaleable Link Interface, but at no time ever has it promised or even hinted at doubling the graphic performance, increasing, yes but double no, unfortunatly people such as yourself who it seems cannot be bothered to do any research will always have the wrong idea and continue to spout mindless nonsense on these boards, I would suggest that you go and research the subject via old PC mags or even Google it.
July 1, 2007 3:24:37 AM

Quote:
Right, first off the term 'Sli' has been around for a long time 1996 in fact and back then it stood for Scan Line Interweave where as now it means Scaleable Link Interface, but at no time ever has it promised or even hinted at doubling the graphic performance, increasing, yes but double no, unfortunatly people such as yourself who it seems cannot be bothered to do any research will always have the wrong idea and continue to spout mindless nonsense on these boards, I would suggest that you go and research the subject via old PC mags or even Google it.


I don't entirely agree with what he is saying, but you may want to edit what you said. Right off of NV's website: "Using proprietary software algorithms and dedicated scalability logic in each NVIDIA graphics processing unit (GPU) and MCP, NVIDIA SLI technology delivers up to twice the performance of a single graphics solution." Now, they aren't fully specific here so it could mean that 2x7900GS' are better than one 7900GT. So right there is a loop hole, but they still did mention double your performance.

SLi zone

ATi is a little vague at how they describe the performance increase. They say it is "boundless", whatever that is supposed to mean. So no argument there.
Related resources
a c 271 U Graphics card
July 1, 2007 5:01:04 AM

Ok, so Nvidia does more than hint at double peformance, but I don't see the point at editing my original post since you have quoted it, thus keeping the original intact.

Quote:
"Using proprietary software algorithms and dedicated scalability logic in each NVIDIA graphics processing unit (GPU) and MCP, NVIDIA SLI technology delivers up to twice the performance of a single graphics solution."


To me that means that I might get up to twice the performance not that I will get twice the performance of a single card ie 2x7900GS's are going to perform better than a single 7900GS and 2x7900GT's are going to perform better than a single 7900GT.

So I have to ask, what Sli setup do you run then?
July 1, 2007 11:50:37 AM

I'm glad lostandwondering is helping you to understand - I've done the research, that's why I made the post. I'm aware of SLI's history. Past history isn't what I'm referring to however. I've seen benchmarks where 2 lower power cards in SLI don't equal the performance of one High end card. That confuses me. It seems the technology was made for high/higher end cards. Now - on the high end side. I understand that there is extra processing that had to occur in a multiple GPU situation - 1 card renders part of the scene, the other card renders the other part. Then there the bridge between the 2 (bridge, interconnect, link, all the same) that must be added into the processing equation, and a whole lot of other technical stuff. I''ve read the reports, and the marketing hype. What might not have been shared (and I mean might) is the bottleneck in the system. Similar to a dual processor, or more processor system. There's overhead (extra) when processing which CPU will handle the data. So even though you have 2 (or) more processors on the board, each extra processor only provides about 40% to 60% more processing power. You paid full price for the other processor however. (I know the situation changes when you have multiple core processors, and todays technology - and pricing is awesome.) This isn't anything new, and I could go on but I'll stop. It's like anything else that is well advertised and hyped up. Marketing makes you think it can do more than it can. Holla Back!
July 1, 2007 12:53:57 PM

Quote:
Right, first off the term 'Sli' has been around for a long time 1996 in fact and back then it stood for Scan Line Interweave where as now it means Scaleable Link Interface, but at no time ever has it promised or even hinted at doubling the graphic performance, increasing, yes but double no, unfortunatly people such as yourself who it seems cannot be bothered to do any research will always have the wrong idea and continue to spout mindless nonsense on these boards, I would suggest that you go and research the subject via old PC mags or even Google it.


I don't entirely agree with what he is saying, but you may want to edit what you said. Right off of NV's website: "Using proprietary software algorithms and dedicated scalability logic in each NVIDIA graphics processing unit (GPU) and MCP, NVIDIA SLI technology delivers up to twice the performance of a single graphics solution." Now, they aren't fully specific here so it could mean that 2x7900GS' are better than one 7900GT. So right there is a loop hole, but they still did mention double your performance.

SLi zone

ATi is a little vague at how they describe the performance increase. They say it is "boundless", whatever that is supposed to mean. So no argument there.

Well, from what i have seen (and experienced), the latest incarnation of crossfire doesn't scale too badly i must say, and when Ati say "Boundless" it is because multiple parts put together can perform better than the sum of their components in some cases. Eg, you have a processing task that will always use a set amount of processing power, lets say 25% on a 100GFLOP card (Call this OP1), and this has to be running, but the entire process won't benefit from it running any faster, then there is another part of the processing that uses say 75% on a 100GFLOP card (call this OP2), and when this processing is done faster it WILL increase performance. So, when you add another card you end up with the 25 percent staying at 25% of one card, but the 75% has now grow to 175%, more than a 2x increase, and theoretically will hence give more than a 2x performance increase, this is an example of 2 parts working as a team to achieve more than the sum of its components. Because if you get 2 cards, and they are doing 2x OP1 and 2x OP2 you are only ever going to get a maximum of 2x the performance (theoretically).

PS, read this review of 2x x1950 pros www.digital-daily.com/video/x1950pro_crossfire/

Also, you said:

Quote:
Similar to a dual processor, or more processor system. There's overhead (extra) when processing which CPU will handle the data. So even though you have 2 (or) more processors on the board, each extra processor only provides about 40% to 60% more processing power. You paid full price for the other processor however. (I know the situation changes when you have multiple core processors, and todays technology - and pricing is awesome.) This isn't anything new, and I could go on but I'll stop. It's like anything else that is well advertised and hyped up. Marketing makes you think it can do more than it can. Holla Back!


Well, actually, it is quite easy to get 2x the performance out of a dual core processor (aka, 100% speed increase), OK, lets say you're converting MP3s, the MP3 conversion software is single threaded, so you are only going to get normal performance, right? WRONG. You see, what you could do is set the affinity of on MP3 converter to one core and the affinity of the other to the other core and queue up half the MP3s in each program, giving you a near perfect 2x increase in performance.

PPS: sorry for annoying you or stating irrelevant facts or incorrect information or near impossibly hypotheticals but I'm going to sleep
a b U Graphics card
July 1, 2007 1:18:40 PM

Remember though, SLI originated years ago when games began to really tax the available technology. As the technology has improved, it seems to me that we kind of sea-saw back and forth between games that tax the hardware to the limit, and hardware that can really crank out performance. My take on SLI is you bite the bullet and buy the best card, or at least one that is very near the top of the list when you build. When you feel the card is aging and starting to struggle, by that time the price you paid for the card will have dropped far enough that adding a second card gives you a relatively inexpensive way to boost your performance.
Just my 2 cents on the whole SLI/Crossfire thing.
July 1, 2007 1:20:23 PM

Quote:
Come on guys - If I have a low to mid range graphics card, and I wanted to really increase my playing experience, I would definitely consider an SLI or Crossfire setup.


I have to disagree with you from the first line here. Don't even consider multi gpu until you have already bought the best single card you can get.
July 1, 2007 1:27:37 PM

what, so back in the day you would have bought a 7950GX2 over a 7950GT/X Sli rig? wishful thinking...
July 1, 2007 1:44:47 PM

the 7950gx2 is 2 cores.. plus it had many problems with drivers, i wouldnt wanna sli em.
July 1, 2007 1:53:37 PM

Quote:
what, so back in the day you would have bought a 7950GX2 over a 7950GT/X Sli rig? wishful thinking...


Nice example, it is a bit of a stretch calling that a single card. Rather than talking about previous generations would you today recommend 2*2600 over 2900 or 2*8600 over 8800?
July 1, 2007 2:04:16 PM

i wouldn't prefer 2x8600vs8800 but i would prefer 2x 8800gts than 1 8800gtx, or i would prefer 2x x1950pros over an x1950xtx, man, some times i would be tempted to even prefer 2 x1950pros over an 8800gts!, seriously, at $110 each and in quite a few games they beat the 8800gts, sometimes i wonder.
July 1, 2007 2:29:20 PM

Quote:
Ok, so Nvidia does more than hint at double peformance, but I don't see the point at editing my original post since you have quoted it, thus keeping the original intact.

"Using proprietary software algorithms and dedicated scalability logic in each NVIDIA graphics processing unit (GPU) and MCP, NVIDIA SLI technology delivers up to twice the performance of a single graphics solution."


To me that means that I might get up to twice the performance not that I will get twice the performance of a single card ie 2x7900GS's are going to perform better than a single 7900GS and 2x7900GT's are going to perform better than a single 7900GT.

So I have to ask, what Sli setup do you run then?

I don't run SLI, I was just pointing out that NVidia mentioned the word "twice" in reference to performance. I agree with you though. Just because I can get twice the performance, it doesn't mean I will. FYI, my response wasn't an attack, I don't think you took it that way, but just stating that.
July 1, 2007 5:25:15 PM

Totally agree! I wasn't advocating 2 low to middle end cards in SLI/Crossfire - at the moment, they don't equal 1 High end card. If they did, my post would have been different. I'm all in favor of getting 1 great card, having a really decent CPU, a great hard drive (RAID if possible), and on and on.
July 1, 2007 5:37:29 PM

I am absolutely tempted to go the crossfire way. And I think you've hit the head on what I was saying - SLI/Crossfire is much more beneficial on High/Higher end cards, like the ones you've mentioned. The X1950 pro dual from Sapphire is the card I want. Yet it is too expensive - about $100 more than it's expected price, with performance at the level of the 8800GTS. In this case, you pay the premium for Crossfire on 1 PCB - no other pieces needed to bridge the cards, no switch needed on the motherboard, etc. But the 1 x GTS is at the same level or faster (according to a couple of benchmarks out there). Interesting right - 2 x1950's should really shine - I mean should blow away any single card combination. I'll stop fussin now. You guys get my point.

Game on - enjoy your machines - Love GOD - take care of your souls - computers won't last, but your soul lasts forever.
July 1, 2007 6:02:15 PM

Being a previous SLI system owner, I can say there was only maybe one time where I actually got 2x the framerate over SLI disabled and it was in F.E.A.R., as it has SLI support built into the game engine. Most other games did not show as large an improvement with SLI enabled; there were even some cases where SLI performed worse than a single GPU.
July 1, 2007 6:34:34 PM

SLI makes alot of sense if, the performance of the fastest graphics card isn't fast enough, in a particalur game at a certain desired settings / resolution.

SLI can scale from 80% to 99% in some games, at particular resolutions and settings. It can also scale negatively (worse performance with two cards), at particular resolutions and settings.

The multiple graphics cards and physics concept, is right now more useless than PhysX... That says a lot.

Last, the CF / SLI chipset locks should be removed from drivers.
a b U Graphics card
July 1, 2007 7:38:36 PM

Who cares?


SLi and Xfire can both offer twice the performance, and even more, but that's an upper limit, not and average or guaranteed level so get beyond that, and your messed up view on how it works, and exactly what's your beef?

For people who have large panel LCD monitors or are AA whores then it makes sense, for most other people they can get the same results from a single cards with a few exceptions (like 2 GF7800GTs performing better for cheaper than a GF7800GTX-512 or 2 GTS-640s for cheaper than a single Ultra at launch).

Anywhoo so we can conclude from your thread, you don't understand SLi/Xfire and you also don't like it. Good to know. :|
a c 271 U Graphics card
July 2, 2007 11:52:27 AM

No my friend I didn't feel attacked just a little disappointed perhaps in the way some people interpret what they read on a companies website, of course a company is going to talk up its products, after they want you to buy into it, its what they exist for, but if you know what it is they are selling and know what to expect then you tend to ignore the gloss and shiny that all manufactures put on their products.

The way I see it graphics cards can be likened to tits and testicles in the way that two will always be better than one. 8)
July 2, 2007 1:35:21 PM

Quote:
The way I see it graphics cards can be likened to tits and testicles in the way that two will always be better than one. 8)


I don't think I've ever thought of it that way....It may not be the most appropriate analogy, but hell it works and I like it! :lol: 
July 2, 2007 1:51:51 PM

lol, not really, but yeah, for tits and balls, it is a given, but for graphics cards... i'm not too sure...
July 2, 2007 2:07:07 PM

I'll put in my $0.02, since i don't see it written here:

SLI/CF is not only concerned with simple framerate increases whether they're increasing at 100% or not.

1) You have more onboard memory, useful for playing at high resolutions.
2) You have the use of somewhat free AA/AF options in some cases.

Two cards handle AA/AF options much better, and take less of a hit than a single card would. However, a sucky card is a sucky card all around. You need at least some decent card to benefit much of anything from SLI/CF.

If it was possible back when the GF5's and the 9800's were out, who in their right mind would bother trying to SLI two GF MX440's? 250/400, No T&L, no pixel shader... why bother? (I overclocked mine to 300/500 which showed a really nice improvement though...)

What i'm saying is that while SLI/CF might not give you the 100% conversion that you're expecting or want, it gives it to you in other ways that you may not be fully capable of extorting from the cards.
a c 271 U Graphics card
July 2, 2007 2:48:02 PM

:lol:  I love playing with a nice pair of tits and whilst graphic cards are not quite as much fun, I still found the experience got better with two 7900 GT’s instead of one.

@Korsen – From your $0.02 worth you sound like you have a much better understanding of the tech than the OP.
July 2, 2007 2:57:49 PM

cmon, no offense but he was actually expecting near 2x performance? that basically shows his/hers understanding right there...
a b U Graphics card
July 2, 2007 3:14:39 PM

Quote:
The way I see it graphics cards can be likened to tits and testicles in the way that two will always be better than one. 8)


ROFL

[wiping tears from eyes and coffee off monitor] :lol: 

Personally my SLI average performance experience is generally 1 1/2 times, with some games higher and some lower, I've never really understood people bashing SLI or CF that aren't even running it anyway.

To me thats like the childrens story of the fox that couldn't get to the grapes high up in the tree, so he told all the passers by that they weren't any good.

I do agree if someone is going to go the SLI route to shoot for the highend cards, so later down the road they won't be disappointed if they know what they're getting into to start with.

I've had my OCd and flashed 7800GTXs in SLI since March of 06 and until the 8800GTX came on the scene they ruled, I don't the first time regret going SLI and if I had the money to spare I'd snag me 2 8800GTX today, thats my future plans anyway, when prices fall some[HOPEFULLY]!

As always good to bump into you out here Al! Ry
July 2, 2007 3:26:27 PM

yeah, i have to agree, and another thing... I don't really see why everyone was raving on about sli when crossfire was just as good? it really never got as much publicity as it deserved, Cmon, i think http://www.tomshardware.com/2006/10/17/game_on_with_the... is the best example of how good it was for its time.
a c 271 U Graphics card
July 2, 2007 3:28:46 PM

Hi Ry, Sorry about the monitor mate :lol:  , less than a day away from the beerfest now :wink: , my stocks are in and I'm limbering up *tsssh from can of Stella* over here on this side on the pond as I trust you are doing similar my friend.

Have a great holiday mate :D  , All the best, Al.
a c 271 U Graphics card
July 2, 2007 3:49:52 PM

As I see it Ati were late to the party and for me it seems as though they are copying, don’t get me wrong I’m not trying to badmouth Ati, but the way I see it is that Nvidia got the original idea/tech they bought/stamped on 3dfx back in the day and it was quite a while between the take over and Sli coming to the marketplace and I cannot recall Ati coming up with anything like their Crossfire solution which I’m pretty sure came out after Sli.

As I have not played about with Crossfire I cannot and indeed will not comment on whether it’s good/bad, makes babies explode, or any of that kind of thing I went with Nvidia mainly because of the 3dfx connection.
a b U Graphics card
July 2, 2007 3:50:11 PM

My choice to go SLI at the time that I was deciding on the parts for my last complete build, was the end of Jan 2006, SLI was on solid ground at the time and Crossfire was just coming on the scene.

I was previously ATI with a 9800Pro and an X850Pro, both excellent cards for their time and both I still have today, I am impressed that CF has moved to the bridge linkup nstead of the external cable hookup, I think thats a great step for them, so really as far as my next complete build is concerned, I'm just waiting to see whats going to happen.

This is the kinda thread where the CF users need to step up and enter their 2 cents, so we can all learn from each other, I'm seriously interested in CFs performance, because I'm still pulling for ATI to pull a rabbit out of the hat as they've done in the past.
a b U Graphics card
July 2, 2007 3:53:50 PM

Quote:
Have a great holiday mate , All the best, Al.



U 2 my friend! Ry
July 2, 2007 4:01:59 PM

@mousemonkey: The funny thing is, i haven't used SLI or CF yet... I just understand from reviews, news articles, etc, how they tend to perform. History simply repeats itself.

Every SLI/CF setup gives you more headroom with higher resolutions, and less of a performance hit when using AA/AF. That's how it is no matter what setup it is. Hell i bet if i could've SLI'd the GF MX440 that i would've gotten some nice AA/AF settings to use without dragging my games into the mud.

To put it hard, if you're playing at anything higher than 1280x1024, then SLI/CF is for you, and obviously you're not playing with low end cards if you've got a monitor that can support over that resolution (like my 21'' CRT :twisted: supporting 2048x1536)

The reason for this, is that at lower resolutions, it becomes CPU intensive, and higher end video cards are not worth paying for since you wont be using the GPU's full power. Playing at the higher resolutions of course, will become GPU intensive, and what GPU you have will make all the difference.

The reason for all these performance differences? Pixel count.
1024x768 = 786,432
1600x1200= 1,920,000
2048x1536= 3,145,728

So you can see why, at higher resolutions, the graphics card is the more important thing, and at lower resolutions, it is less important. Oh, and to really insert the value of these numbers: The GPU must render those pixels as many times per second as it can, prefferably 30 times per second, if not 60. Let us see what this ends up being:

1024x768 @ 30FPS = 23,592,960
1600x1200 @ 30FPS= 57,600,000
2048x1536 @ 30FPS= 94,371,840

That's how many pixels per second the GPU must render, and it becomes much more obvious here why SLI/CF can be very useful. Doubling the resolution quadruples the amount of pixels needed to render per second. And i got those numbers by multiplying my first set of values by 30(FPS).

Just for the hell of it, let's see what the GPU needs to render for a perfect 60FPS gameplay:

1024x768 @ 60FPS = 47,185,920
1600x1200 @ 60FPS= 115,200,000
2048x1536 @ 60FPS= 188,743,680

Remember, these numbers are pixels rendered PER SECOND. Still think SLI/CF is useless? Nevermind the overhead from the drivers, nor the fact that the CPU needs to divide the rendering task between two cards in a specific way, or the fact that both GPU's need to send their output to ONE VGA/DVI out... SLI/CF is jumping through hoops here in order to bring you that lovely 70% increase in power and the somewhat free AA/AF settings...

And one last thing, don't forget about all those OTHER, GPU intensive tasks, such as DX10 effects, which are currently crippling the so-called "built from the ground up for DX10" cards. It's not only pixels that the GPU needs to worry about, but all the code it needs to digest... So be happy that you get at least 70% increases in performance for mostly everything.

EDIT: So much for fill rate...
a c 271 U Graphics card
July 2, 2007 4:34:20 PM

8O :)  TBH mate I've never done or should that be 'tried' to do the pixel counting math’s and I run 1280x1024 as that’s as high as my monitor will go, the refresh rate is @60hz as going any higher makes no difference as far as I can tell, even if I use the DVI I/O’s as I am doing.

The performance boost is quite evident however and requires no calculator at all, but it’s good fun to run Rivatuner’s fps OSD on a ‘before and after’ test and watch the frame rate go up and then to turn up the eye candy and see how much it doesn’t go down by :p  , nerdy I know, but hey, it keeps me off the streets at night :lol:  .
July 2, 2007 4:45:03 PM

Well, over my time, i have had quite a large number of multi card setups, 5, infact, all for various reasons and from various manufacturers.

My first Multi-card setup was a Sli setup, because there was nothing out (at the time) that could deliver that kind of performance (remember Ati being a couple of months late?), it was 2x 7800GTs (overclocked 450/1550) and performed great, about that time, some other games came to the table, and i though, well, whilst i have the equipment why not go for an upgraded Sli again, I went out and got 2x 7900GTXs and put them in sli, there was optimally, about a 30% increase over my 7800GT Sli setup, not really what i wanted, but enough. By now, Atis x1900 series was out and well established, but there were no crossfire reviews i could find, jus single card ones, they seemed to be going Very Very well, so i decided to hit it up and find out what it is like, so i got 2x x1950xts (well, one was a crossfire master but meh), the performance increase in games that i played was another huge gain, about 40% over the nvidia cards, i was very pleased, this was the last of my high end multi card solutions, it lasted me right up until the R600 release, but in the meantime, i had built a lan party rig, and with the dwindling price of x1950pros and their stunning price to performance ratio i bought a pair for my lan party rig, it still has them now, in somethings they even out perform an 8800GTS quite well. Quite some time ago (when they first came out) i bought a 30" dell monitor, i thought i would be good because of my high end computer and great computer speakers (logitech z5500s), and it was, so on the release of the R600, before any reviews had been released, but products were on sale, i snapped up a pair, i play all my games on max settings, with no aa/af, because of 2 reasons, with a screen res this big, you don't see jaggies, and 2, it kills performance. the other day after seeing a review between 2 2900xts and 2 8800gtx sli and seeing that at my res and settings that the cards were on an equal level in performance i realised i had done the right thing.


so, thats my experience with sli and crossfire, i have been recently thinking of swapping out my x1950pros in my lan party rig for an 8800GTS because of DX10, but haven't because of how big of a performance killer it is and because my 1950pros generally beat it in dx 9 games.

Oh, by the way, yes, i am well off, but i'm away from home alot so that kinda counters my great pay rate.
a b U Graphics card
July 2, 2007 8:44:36 PM

Quote:
As I see it Ati were late to the party and for me it seems as though they are copying, don’t get me wrong I’m not trying to badmouth Ati, but the way I see it is that Nvidia got the original idea/tech they bought/stamped on 3dfx back in the day and it was quite a while between the take over and Sli coming to the marketplace and I cannot recall Ati coming up with anything like their Crossfire solution which I’m pretty sure came out after Sli.


I'm a little sick of people always saying ATi copied nV when in fact if anyone copied anyone else, nVidia copied ATi. If it weren't for ATi and Metabyte's IP, nVidia would have no multi-vpu solution.

http://www.firingsquad.com/hardware/nvidia_nforce_4_sli...
http://www.xbitlabs.com/articles/video/display/crossfir...

AFR is ATi's idea, SFR is Metabyte's, Tom's had a good review of the old systems but it's gone, out of the two which do you think works best? And why do you think nVidia doesn't use their own SLI if it's a continuation of their idea from 3Dfx and not someone else's?

As for the push to market If anything Alienware revived interest in multi-card solutions to the mainstream when they bought Metabyte's IP in order to start making their ALX multi cpu / multi-vpu solutions, which ended up being a failure due to the software burden and was eventually replaced by SLi even in ALienware's rigs (better to get nVidia to makes drivers work than a system builder do all the work).

But nVidia didn't even restart the revolution, that would be ATi with the R9800MAXX and then XGI with the Volari V8 Duo. Neither were succesful and only XGI made it to market (with lots of driver issues), but it's not like nVidia did anything that hadn't already been on other people's plates.
ATi also used Suptertiling in simulators long before nVidia made their first multi-card solution (3Dfx doesn't coun't because it wasn't under nVidia and SLI died with the last Voodoo). And even 3Dfx weren't the first to do it, only the first to do it in the consumer space. One of the best reviews on this was from Beyond3D but their archives got wiped when Hexus bought them, same as what happened to Tom's old archives.

Quote:
As I have not played about with Crossfire I cannot and indeed will not comment on whether it’s good/bad, makes babies explode, or any of that kind of thing I went with Nvidia mainly because of the 3dfx connection.


Yet nVidia's solution had nothing to do with 3Dfx other than they used the SLi name to confuse people into thinking they were doing something they'd done before, when in fact they are doing what the opposition did before, and without which they couldn't make their solution work anywhere near as well.

SLi is definitely more widely supported, but I don't see it as better or worse than Xire, and the argument that ATi copied nV ignores the reality that it was the other way around.
a c 271 U Graphics card
July 2, 2007 11:12:07 PM

I stand corrected, and truly humbled by your knowledge sir
July 3, 2007 2:03:04 AM

From my experiences, Sli scales more stably (aka, a predictable result increase in most games), but Crossfire scales better but is less stable (aka, in some games there will be no difference, or a negative difference, but in other games it will scale much much better when it does actually scale).
July 3, 2007 2:26:51 AM

Quote:
I'll put in my $0.02, since i don't see it written here:

SLI/CF is not only concerned with simple framerate increases whether they're increasing at 100% or not.

1) You have more onboard memory, useful for playing at high resolutions.
2) You have the use of somewhat free AA/AF options in some cases.

Two cards handle AA/AF options much better, and take less of a hit than a single card would. However, a sucky card is a sucky card all around. You need at least some decent card to benefit much of anything from SLI/CF.

If it was possible back when the GF5's and the 9800's were out, who in their right mind would bother trying to SLI two GF MX440's? 250/400, No T&L, no pixel shader... why bother? (I overclocked mine to 300/500 which showed a really nice improvement though...)

What i'm saying is that while SLI/CF might not give you the 100% conversion that you're expecting or want, it gives it to you in other ways that you may not be fully capable of extorting from the cards.
SLI and Crossfire do NOT add memory, and sure two of the same card will perform better than one with antialiasing, but that doesn't mean it's better than everything else. The closest to a card getting free antialiasing is the 8800GTX.
July 4, 2007 6:43:39 AM

i know this is a little off track but who is this Tom Shardware guy i see everywhere?
July 4, 2007 7:59:19 AM

Quote:
(like my 21'' CRT :twisted: supporting 2048x1536)


Is that a Sony G-series? If it is, I hate you. so...very...much :lol: 

Quote:
The reason for all these performance differences? Pixel count.
1024x768 = 786,432
1600x1200= 1,920,000
2048x1536= 3,145,728

So you can see why, at higher resolutions, the graphics card is the more important thing, and at lower resolutions, it is less important. Oh, and to really insert the value of these numbers: The GPU must render those pixels as many times per second as it can, prefferably 30 times per second, if not 60. Let us see what this ends up being:

1024x768 @ 30FPS = 23,592,960
1600x1200 @ 30FPS= 57,600,000
2048x1536 @ 30FPS= 94,371,840

That's how many pixels per second the GPU must render, and it becomes much more obvious here why SLI/CF can be very useful. Doubling the resolution quadruples the amount of pixels needed to render per second. And i got those numbers by multiplying my first set of values by 30(FPS).

Just for the hell of it, let's see what the GPU needs to render for a perfect 60FPS gameplay:

1024x768 @ 60FPS = 47,185,920
1600x1200 @ 60FPS= 115,200,000
2048x1536 @ 60FPS= 188,743,680

Remember, these numbers are pixels rendered PER SECOND....


Wait until the Ultra HD television standard is introduced next decade (approx 2016 in Japan anyway).

7680x4320 = 33,177,600 pixels.

7680x4320 @ 30FPS = 995,328,800 pixels per second
7680x4320 @ 60FPS = 1,990,656,000 pixels per second

And we all thought that graphics technology is staying ahead of games :lol: 

I'd hate to be the poor artist for a game supporting that resolution though.

I'm not expecting Ultra HD to hit mainstream until 2020's though.
July 4, 2007 8:11:01 AM

lol, yeh, my dell 3007wfp is 2560x1600, but i read somewhere that there is a manufacturer that is making tvs that have 4x the res of 1080P (2x height, 2xwidth) for testing already and will be on the market towards the end of 2008...
July 4, 2007 8:33:45 AM

Quote:
lol, yeh, my dell 3007wfp is 2560x1600, but i read somewhere that there is a manufacturer that is making tvs that have 4x the res of 1080P (2x height, 2xwidth) for testing already and will be on the market towards the end of 2008...


Yeah Viewsonic has had the vp2290b out for a few years (3840x2400)

review:

I found this on the wikipedia Ultra HD page, so take it as you will:

Quote:
Eighteen minutes of uncompressed UHDV footage consumes 3.5 terabytes of data and one minute of uncompressed footage consumes 194 gigabytes (2 hours of full length movie will use roughly 25 terabytes of storage).
a b U Graphics card
July 4, 2007 10:45:21 AM

The prob with SLI and XFire is that performance is not absolute. This has to do with overhead, how a game was made and driver issues. The prob here is how to render a 3d scene effectively, that's what nvidia and ati are doing, finding the best general render method that would work in most scenarios.

Also the general recomendation is to get one higher end card than 2 mid-end cards due to the price-performance-compatibility difference. I believe that nvidia initially stated SLI as an idea to be able to slot-in just another card if you feel sluggish performance. The prob is that by the time that there is a significant price-drop on the same part, a new model is out and the difference is not only with speed but compatibility. This becomes like the issue of getting a DX9 card in the start of a DX10 era.
July 4, 2007 2:11:14 PM

Quote:
lol, yeh, my dell 3007wfp is 2560x1600, but i read somewhere that there is a manufacturer that is making tvs that have 4x the res of 1080P (2x height, 2xwidth) for testing already and will be on the market towards the end of 2008...


Yeah Viewsonic has had the vp2290b out for a few years (3840x2400)

review:

I found this on the wikipedia Ultra HD page, so take it as you will:

Quote:
Eighteen minutes of uncompressed UHDV footage consumes 3.5 terabytes of data and one minute of uncompressed footage consumes 194 gigabytes (2 hours of full length movie will use roughly 25 terabytes of storage).
8O

So I take it Blue-ray is NOT the future :D 
July 4, 2007 4:20:26 PM

Anyone out there running crossfire with dissimilar video cards - i.e. X850 and x1950 pro? How's it working? I just remembered you could do this with a Crossfire setup.
a b U Graphics card
July 4, 2007 4:49:33 PM

You can't do that with a crossfire setup.

You can crossfire an X1800GTO and X1800XTCF or an X800Pro with an X800XTCF and the like but not things that have greatly different architectures, no X800 + X1900 and not even an X1800 + X1900.
July 4, 2007 5:04:40 PM

Thanks for clearing that up for me.
July 4, 2007 5:25:44 PM

Face it people parallel is the future... SMP is going to take over eventually so might as well welcome it. Soon we might all be using 50 cores, or more.

CRAP! C R A P! better post an extra reply to get rid of this evil count.
July 4, 2007 5:28:08 PM

I think he means using one card for physics. BUt i am not sure if the old ones will even support that.
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