I plan to build a new system in early-mid fall, depending on what's going on with the technology at the time. I wanted to know what are the advantages of dual cards (SLI, cross fire) over a single card? It seemed like an awesome idea at first, but I read some posts about how it's not that great after all. What does two cards actually provide? sorry if this has been asked before. the search function doesnt want to be my friend.
If you want better performance than an 8800GTX (or Ultra) can provide, the only way to do it is with SLI.
SLI with low or mid-range cards is usually a dumb idea as a single high end card will offer better performance at a lower cost. The high end card will allow a better upgrade path if you choose to SLI later on.
The claim is double the cards, double the performance. This is rarely the case. You will definitely get more FPS in your games, but most likely not double the rate, thus making it a waste of money in most cases. The other advantage to having SLI or XFire is that you can say you have it... bragging rights in other words.
Some time ago I was thinking let's get an 8800 GTX now and add another in a year when new games need more power. I gave up. It's smarter to sell the one 8800 GTX and buy one new high-end card from the next generation (8900 GTX or whatever they'll call it), it will do much better than the 8800 GTX SLI and with less noise/power/heat. Go for SLI if you want and can afford two cards right away. Don't go for SLI if you can only afford one card now and you'd like to add another later. Just my 2 cents...
My bench mark went from 9800 to 17800 in SLI pretty close to double the performance, and what guaranty is there that the next single card generation will out preform a 8800 SLI setup.
My bench mark went from 9800 to 17800 in SLI pretty close to double the performance, and what guaranty is there that the next single card generation will out preform a 8800 SLI setup.
these are internet tails ignore them.
If you wanna believe that i put a vodoo 3 in my 486dx2 66mhz and it got a score of 02983478903274981723 49817 43413409 -30298340 best score every. I would of got a screenie put i am not sure how to post it.
If you want better performance than an 8800GTX (or Ultra) can provide, the only way to do it is with SLI.
SLI with low or mid-range cards is usually a dumb idea as a single high end card will offer better performance at a lower cost. The high end card will allow a better upgrade path if you choose to SLI later on.
My bench mark went from 9800 to 17800 in SLI pretty close to double the performance, and what guaranty is there that the next single card generation will out preform a 8800 SLI setup.
Nice setup you've got there...
The benchmark programs are easier to write than games. Games might not do so good. Based on countless charts and fps numbers I've seen on the Web I'd say SLI adds 20% to 80% to the fps depending on game, resolution, settings, CPU, even RAM, even where in the game you are (as in Oblivion indoors vs outdoors). It's just nuts.
The next card - there's rumour about the 9800 GTX due for Christmas and doing something like a teraflop. That would be more than twice the 8800 GTX. There was a big thread about it. Must admit I didn't understand all of it but still useful. Of course, it's just rumours.
We can try a guess based on previous cards: one 8800 GTX beats two 7800 GTX in SLI, doesn't it? One can always hope to see this sort of thing happen again
The claim is double the cards, double the performance. This is rarely the case. You will definitely get more FPS in your games, but most likely not double the rate, thus making it a waste of money in most cases. The other advantage to having SLI or XFire is that you can say you have it... bragging rights in other words.
I agree you will rarely if ever get double the performance but depending on the game or app, it can get pretty close.
I have the Sli load balancing graph enabled on my computer and can see how much work each card is doing. It is obvious that many games are just not optimized to work best with an SLI system.
In comparison if you test SLI on an Nvidia demo that is optimized for SLI, the load balancing on both cards is maxed out, meaning both cards are working their hardest at the same time.
So a small gain in some games with SLI is not necessarily the fault of SLI or Crossfire for that matter. It is more related to how the game or app was built.
You do in fact have the power of two and as more new games come online I see the benefit of SLI increasing.
So you're saying SLI will work better and better as game developers learn to use it properly? I sure hope you're right 8O
Also don't forget that performance tends to increases with driver updates. I have high hopes for Crysis since it was developed on Nvidia and SLI platforms. If they can have a version optimized for SLI like Nvidia's own demos, Crysis will Rock! on SLI.
well, two cards can be very useful if the drivers support the games.
i bought one card in january the other in august and i can say i regret not doing it sooner, then again the drivers have been getting better since i bought it.
of course the game that supports it best that i own is oblivion. for one i cannot play it at the settings i use with one card, secondly i do get roughly x2 performance. so by that measure it is worth it.
of course if you ain't got that much money and play using a 17-19" LCD don't bother. if you are the opposite, it is well worth investing in if you want the best possible performance.
We can try a guess based on previous cards: one 8800 GTX beats two 7800 GTX in SLI, doesn't it? One can always hope to see this sort of thing happen again
Wow, my bad, I have no clue what I'm talking about, sorry
Those charts show the 7800 GTX SLI about 15% better (that's 1.15 times, OK?) than the 8800 GTX SLI. Didn't expect that at all.
However, they are all from Flight Simulator. Could it be that that game is badly written and/or bottlenecked by the CPU and/or not optimized for the 8800 GTX and/or tested with 8800 drivers that didn't support SLI yet?
Look at these, all I did was take your links and change the game to the other games there:
To summarize, the 7800 GTX SLI beats the 8800 GTX SLI, by a negligible margin, in one game out of 7 they measured. The 8800 GTX SLI wipes the floor (talking 2, 3 or 4 times the fps here) with the 7800 GTX SLI in the other six. In some of them the 8800 gives a nice 45 fps while the 7800 is a 12 fps slideshow.
And you declare the 7800 GTX SLI the winner? Sure, go ahead, but I'm not convinced.
OK, what we were really discussing was ONE 8800 GTX vs TWO 7800 GTX. Any benchmarks for that?
Original poster: please play with these URLs to make up your own mind. It depends on the games you have, the settings, the resolution, the CPU, the O/S, the amount of RAM, etc etc. You may get a huge benefit from SLI or not.
And you declare the 7800 GTX SLI the winner? Sure, go ahead, but I'm not convinced.
WHOA Dude, I just posted some benchies ran by THG to show that even though the 8800GTX single card should by all rights be solidly king of the hill, that even in SLI and running some software like the Flight Sim X it isn't, but that only applies to that particular game and software combination, not to other games.
Now in FSX in the lower resolutions with both the 7800GTX and 8800GTX running in SLI the 7800 outperforms the 8800, only in the higher resolutions does the 8800SLI start to pull past the 7800SLI, and we're only talking a couple of frames per second, thats not a floor wipe.
I wasn't claiming the 7800GTX SLI the winner as you said in the quote, just posting benchmarks that you might not be aware of, basically Flight Sim X is kicking every card in the dirt pretty much across the board, and it probably is CPU bottlenecking, since the game leans more towards the CPU than other games do.
The benchies surprised me because I wouldn't have thought in any game what so ever, and under any resolutions, that a 7800GTX SLI could ever best a single 8800GTX, much less if the 8800GTX was also in SLI, I'm not trying to offend you here and if it came across as such, I apologise. Ryan
Nowadays you can purchase a single video card that will run high resolutions with most,if not all,the eye candy enabled.I personally like SLI and have been running it for a year or so now.I started with 2 7800gt's.I just recently(3-4 months ago),purchased 2 7950GT KO video cards,and I just love the performance from the two cards.One card has been RMA'd due to vram issues,But man the extra horsepower is nice to have when you need it.Goodluck.
Dahak
AMD X2 5600+ @ 2.8ghz(stock) M2N32-SLI DELUXE MB 2 GIGS DDR2 800 RAM THERMALTAKE 850WATT PSU 7950GT KO(WAITING FOR MY OTHER TO COME BACK FROM RMA) ACER 22IN. LCD SMILIDON RAIDMAX GAMING CASE 80GIG/250gig SATA2 HD's XP MCE
Wow, my bad, I have no clue what I'm talking about, sorry
Those charts show the 7800 GTX SLI about 15% better (that's 1.15 times, OK?) than the 8800 GTX SLI. Didn't expect that at all.
However, they are all from Flight Simulator. Could it be that that game is badly written and/or bottlenecked by the CPU and/or not optimized for the 8800 GTX and/or tested with 8800 drivers that didn't support SLI yet?
Look at these, all I did was take your links and change the game to the other games there:
To summarize, the 7800 GTX SLI beats the 8800 GTX SLI, by a negligible margin, in one game out of 7 they measured. The 8800 GTX SLI wipes the floor (talking 2, 3 or 4 times the fps here) with the 7800 GTX SLI in the other six. In some of them the 8800 gives a nice 45 fps while the 7800 is a 12 fps slideshow.
And you declare the 7800 GTX SLI the winner? Sure, go ahead, but I'm not convinced.
OK, what we were really discussing was ONE 8800 GTX vs TWO 7800 GTX. Any benchmarks for that?
Eisen6faust 
dalcamp@hotmail.com 