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3 Video cards?

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July 19, 2006 6:59:39 PM

Guys,

I've read THGC article "Six 975X Enthusiast Motherboards for Today and Tomorrow" and I became confused about something. They have 3 video cards in there which allow for support of up to 6 monitors. (Take a look HERE and scroll to the middle of the page. )

Okay, 6-monitor support could be useful to some, but what other purpose can this serve?

Q1. Would it be two cards in SLI / X-Fire + the third card for physics or what's the deal?

Q2. This Intel motherboard has

- One Primary PCI Express x16 ( electrical x16 or x8 ) bus add-in card connector
- One Secondary PCI Express x16 ( electrical x8 ) bus add-in card connector
- One PCI Express x16 ( electrical x4 ) bus add-in card connector

Apparently they have a GeForce 6800 in the x4 slot. Why?

Q3. Why is this last slot x4?

More about : video cards

July 19, 2006 7:29:54 PM

Quote:

Q3. Why is this last slot x4?

Because chipsets are limited in the number of PCI-E lanes they support. The board was probably out of extra lanes so they made the 3rd slot 4x.

-mcg
July 19, 2006 8:09:48 PM

I doubt it's the reason, but ATI was/is looking into a 3 slot setup for their physics solution.

The bad part is that according to the THG Game Over article, the 975X boards aren't as Conroe compatible as many people were lead to believe according to various info floating around the web, due to the PECI feature of the Core architecture.
Related resources
July 19, 2006 8:24:36 PM

Quote:
The bad part is that according to the THG Game Over article, the 975X boards aren't as Conroe compatible as many people were lead to believe...


Okay. Conroe or not :)  I am now even more confused: I looked up some tech info on PCI Express and learned about different connectors (x1, x4, x8, x16)

Looking at this Intel motherboard it appears that it has the following connectors:

Two x16
Two x8 electrical (what the heck is this "electrical" thing?)
One x4

So, I went to NewEgg.com and tried to find PCI Express x8 video cards. Found NONE.

Now, what kind of GeForce 6800 do they have in that x4 slot? According to THIS,

"Connectors for the 1x PCIe slot and the 16x PCIe slot are different sizes because they support a different number of bit lanes. The connector sizes for 4x and 8x PCI Express are also different, for the same reason. The PCIe 1x connector has 36 signal pins, the 4x connector has 64 signal pins, the 8x connector has 98 signal pins, and the 16x connector has 164 signal pins. A PCI express card is upward compatible, so a 1x card will fit in any card slot, a 4x card will fit into an 8 or 16x port and so on. An adaptor card using 16x lanes will only fit in a x16 size connector.."

But I have not been able to find any PCIe cards other than x16

Could someone please help me figure all this out?
July 19, 2006 8:36:27 PM

When they say "electrical" they mean that the slot has that many PCI-E lanes actually connected to the slot. So from the sound of things there is one true 16x slot, a 16x slot that runs at 8x, and another 16x slot that runs at 4x. My guess is that when the first two slots are filled they both run at 8x, and only one of the two is capable of 16x operation due to the way it is wired.
As far as I know all currently availible graphics cards are built for 16x slots (although they are capable of running with fewer lanes they require a slot that is "16x long". They probably put the 6800 in the 4x slot because it is the slowest card and needs the least bandwidth across the PCI-E bus.

-mcg
July 19, 2006 8:41:14 PM

Great explanation, man. Thanks. It is all clear now. I have two more quick questions though:

1. Are there any motherboards that have ... ahem ... 3 true 16x slots that would actually run at 16x? (Cuz it seems like a waste to have two 16x cards running at 8x each...)

2. For what reason (other than the obvious cost reason) would Intel limit the slots to 8x and 4x?
July 20, 2006 1:21:02 PM

Okay, seems this thread is going down. Have to bump it up. Sorry. Still would like to know:

Quote:
1. Are there any motherboards that have ... ahem ... 3 true 16x slots that would actually run at 16x? (Cuz it seems like a waste to have two 16x cards running at 8x each...)

2. For what reason (other than the obvious cost reason) would Intel limit the slots to 8x and 4x?


While I am waiting for the next gen CPUs / GFX cards I thought I might begin to purchase some components, such as a future-proof motherboard. That's why I am asking...
July 20, 2006 5:23:02 PM

To my knowledge, there are no motherboards that currently support 3 full 16X PCI-E slots. Only boards like the Asus A8N32-SLI Deluxe support 2 full 16X PCI-E slots. According to X-Bit and AnandTech, having 2 full 16X PCI-E lanes isn't really any better than running two PCI-E cards across 2 8X PCI-E lanes. Those 2 reviews are a little old, so there may be more current info available on this.

Like I noted earlier, ATI solution to physics involves using up to 3 PCI-E graphics cards and I believe they demo'd a 3 card setup (RD600, supposed to be Intel only) recently but it's still in development. Rumor has it that it is supposed to be release before Q4 06.
a b U Graphics card
July 21, 2006 5:32:49 AM

Quote:

1. Are there any motherboards that have ... ahem ... 3 true 16x slots that would actually run at 16x?


No, the best is a Tyan board we discussed here a few weeks back that has 4PEG16X slots 16 + 16 + 4 + 4 lanes;
http://www.tyan.com/products/html/thunderk8qe.html

Quote:
(Cuz it seems like a waste to have two 16x cards running at 8x each...)


Well first of all it doesn't matter much if they run at 8X as we saw in the early SLi and Xfire mobos which were all 8X + 8X until recently.

Quote:
2. For what reason (other than the obvious cost reason) would Intel limit the slots to 8x and 4x?


As was mentioned lanes, but it's not the cost of the wiring or layers, the chipsets only support a certain fixed number of lanes, heck just previously the limit was a total of 20-24 lanes with most being about 22. The current average is 40-48 on the 32X= chipsets (which have 16+16 for SLi/Xfire) and others for other things like other PCIe/PCI connectors, raid controllers, onboard audio, usb, ethernet, etc. In order to support the 3 PEG16X slots you would need 48 lanes for that alone, without support for anything else. Adding support for more lanes costs more more, and can generate more heat, so there's little rush for the chipset makers to just make it 64 lanes or something, but that will likely come too, once process shrinks make it more viable, or the need becomes so great it's worth it (over the alternative of 2 chips).

Speaking of which, that Tyan board actually uses multiple nVPRO (Crush) chipsets which each have their own independant lanes, which gives it more options.

The upcoming RD600 has 48lanes just like the RD580, the nV500 series has 46 lanes, so neither could support 3 full speed PEG16x slots, so that will have to come from the next generation or with added help.

Some added reading, including newegg buyers mentioning Conroe support added to the later revisions;
http://www.theinquirer.net/default.aspx?article=32915
http://www.xbitlabs.com/articles/cpu/display/opteron-ws...
http://www.newegg.com/Product/Product.asp?Item=N82E1681...
July 22, 2006 6:08:00 AM

Thanks, guys. Special thanks to TheGreatGrapeApe. Finally, I don't feel quite out of the loop anymore. I shall keep on reading still.

Ideally, I would like to get a future proof motherboard... with 48 or 68 lanes or whatever - the more the merrier :)  - which would last up to 5 years (I know, I know. 5 years seems too long. But I am pretty sure PCIe will remain standard for very long time and even if they come out with PCIe x32 in five years I am sure I can use a card like that in x16 and it will work just fine like it was with AGP 8X in 4X slots. Also I want my machines to pass reality tests: To me benchmarks are meaningless. If I can run every game/application out there without problems, I don't care if someone gets double my score in 3DMark0x). With my machines I typically skip up to 3 generations of video cards....

Thing is that in my experience one never upgrades a motherboard. As I mentioned before, I build my PCs rarely (once in 2.5-3.5 years) but I use premium everything, so they last. Even if one adds memory, a hard drive or two or a better video card or whatever, the motherboard stays the same pretty much till it is time to retire the system and build a new one. I only had to replace a motherboard once since 1989 and only because I messed up while overclocking and burned it.

Since I am going to keep my Gf6800 Ultra PC until the next gen video cards arrive I am prepared to wait for a motherboard as well.

So one quick question, Grape: When do you think there will be a chipset supporting 48 lanes or more?

To me heat should not be an issue. I am thinking THIS or similar + watercooling.
July 22, 2006 7:08:35 AM

Q1:
Ati is going to be releasing there new answer to gfx / physx performance(late q4 06'or early q1 07'). At a press release in Taipai, they showed a mobo with 3 pci 16x lanes...two of them with x1900xtx...running in crossfire config...while the 3rd cards focuses on physx...a little x1600 (didnt need to be overly powerful since its primary forcus was on physx) the nice thing about this configuration that beats the ageia card completely, Is that the phsyx card also can focus of delivering dynamic shadows and shaders to each model reacting in real time, this allows for the main cards to focus on the "general game performance" completely eliminating any lag that ragdoll objects could possibly create.
Ageis says they can do that, but the ageia card still relies too heavily on the gfx cards.

This is going to be an Ati only feature, so far i have yet to hear of any comebacks from nvidia. Although i can only imagine what kind of psu requirements that will take.

And no the motherboard is not out yet....

Before pcie came out there was talk of upgrading the bandwidth once pcie became standard...ill give it about 2 years then there will be another like pcie 32x. As memory and graphics become faster so will the bandwidth between the gfx card and cpu....bottlenecks won't be permitted.
a b U Graphics card
July 23, 2006 2:20:20 PM

Quote:

Since I am going to keep my Gf6800 Ultra PC until the next gen video cards arrive I am prepared to wait for a motherboard as well.

So one quick question, Grape: When do you think there will be a chipset supporting 48 lanes or more?


Well like I mentioned the ATi RD600 is supposed to have 48 lanes (note: I mistakenly thought the RD580 already did which it appears to not be the case (40lanes according to ATi's description [I blame the Gods for my mistake :twisted: ] and the nV5xx is 46 like I mentioned or 48 lanes depending on which kind of shrooms Anand's gang did that week :roll: ), But even with the RD600 that's 'just' the 48 lanes, the significantly 'More' unfortunately I think is going to be a while (think in terms of years [at least 12months IMO]), BUT as we already mentioned one of the benifits is that it's not fully needed yet, however perhaps ~54 lanes might be only a refresh away if there becomes a compelling reason. Unfortunately I do not see the flexability in nV's SPP configuration as in ATi's assignable lanes configuration, so I'm not sure how that plays out, but knowing nV there's probably an answer to any question on a drawing board somewhere.

Main reason no 48+ chipsets yet is as we mentioned these cards don't need the 16X to perform 'normally, just to do dongle/SLi-less multi vpu processing with communication across the lanes, and with both ATi and nV's CURRENT application of multi-Vpu it will be 16+16 thus leaving you with 8-16 lanes left over. So thinking of the max option we have '48', the mobo designer could make 8 of that extra 16 for the third PEG16X slot (running 8X), now you have another 8X left for the peripherals, which right now seem to run on a 4X tunnel called A-Link Express II to the SB600, nv use an SPP+MCP configuration that works differently it somewhat 'pre-splits' lanes between them similar to the CRUSH solution (30 fron the SPP/NB and 18 from the MCP/SB). So even with that configuration you cuold bang out 16+8 on the NB and 16 on the SB, the annoying facet of it though is, does this 'inellegance' cause any reason for concern? I doubt it, but it's a little more annoying than knowing you have a straight numer of lanes. Of course ATi's PR guys are all over it, but I don't see it being an issue initially (if ever).

Ok now that's the now, and the 'now' vision of the future, but let's consider what we know about SLi/Xfire now applied to the future (still can't consider R600/G80 Xfrie/SLi 'til we know more). Right now Xfire can use supertiling for the rendering which theoretically make multi-VPUs a somewhat unlimited commodity (assign the 32 tiles to 1,2,3,4,5,6,7,8,,,, to 32 VPUs like Evans & Sutherland? maybe, that's sure what they were implying in their launch and pre-launch info was that future), now nV has working 4 GPU rendering (technically not quad SLi, but SLi+SLi) and even early GF7900GX2 reviews showed 'Tri-SLi' because the drivers weren't using the 4th card. So the possibility is there for full 3 card mult-VPU rendering from both companies, the pssibility of 6 vpu rendering from an Xfire Gemini setup, and depending on the maturity nV's AFR+SFR driver support probably they too could offer it with 3 GX2s. Now at that level dongle/link-less SLi/Xfire would likely require the full 16 lanes. However should you worry about it, IMO no. By the time you would be concerned about that, you'll likely be concerned about getting other new features on offer to som might as well replace the mobo despite your dislike of tinkering with the upgrading. The reality is right now and for the immediate foreseeable future there is no other option, and be it for physics or multi-vpu likely the 16+16+8 will be more than enough for the usual 3 card seetup (only the GX2 cards pose a potential issue IMO [gemini cards work slightly differently, and reduce the risk, but may also pose another problem as well]).

So IMO you won't see anything above 48 lanes for a while, so buy the best solution you can find from whomever you find has the features you want. It should be somewhat future-looking but like most of us here say, there's no such thing as futureproofing, it's too difficult, and even really saying it ignores the fact that in 2-3 years everything will have changed again, especially on the graphics front, but IMO on the MoBo front too, AMD may do something more on the CPU front (but quad core is now almost 2008, directconnet2 in 2008, DDR3 in 2008), but I think Intel is a set thing for the next 2+ years (probably until DDR3), especially since quad core for them is supposed to have one 775 pin compatible line. I personally think for the dual/quad VPU + physics the current 3 PEG slots will be fine to take you into the future with what we've got coming out this summer.

Needless to say really, but no matter what you choose, I can GUARANTEE a twinge of regret of somekind on whatever you chose for some unknown/unanticipated reason.

Now some of this is crystal ball gazing on my part, but it's based on the realities and published rumours out there, so hopefuly it makes ense and adds a good view of the future possibilities.
July 23, 2006 5:37:56 PM

TheGreatGrapeApe wrote:

Quote:
<...>I mistakenly thought the RD580 already did which it appears to not be the case <...>


Man... will I ever know half of what you know? I am not ass-kissing. It is just that you are always so well-informed, I feel like an idiot :oops:  Thanks! You will be the first to know when I finally build a 22nd century rig :D 
a b U Graphics card
July 23, 2006 5:56:28 PM

Well thanx mang. 8)

And really the more you learn the more you know you have more to learn.
I just wish I had access to the information AMD/ATi/Intel/nV engineers have, because you know that they already know where the '60 lane MoBos' are in their plans, they're just not sure of the time frame which is dictated by demand, etc. so it may be brought forward or pushed back (look at the G80/R600 situaiton with Vista IMO).

I try and be helpful, even if it's just to offer comic relief like in your 'ultimate gaming rig' thread. :twisted:

Anywho, good luck with the build, remember building is half the fun, enjoy! 8)
!