9800GX2 + 88/9800GT: multi-GPU2 in same system?

[Leonardo]

I have a system running dual GPU2 clients containing an 8800GT and a 9800GT. I have a 9800GX2 in shipping and had planned on replacing one of the 88/98 cards, leaving the other card in installed in the computer in the second PCI-e slot for a mutli-GPU machine, count of three. It just dawned on me that the each halve of the GX2 has 128 stream processors, as compared to the G92-based cards' 112 each. If you make the GX2's cores GPU 0 and GPU 1 and the 88/98 core GPU 02, what kind of impact will that have on the third GPUs performance. You know, the usual bad news of mixing Nvidia cards with different GPU architectures? (I think I know the answer, I just want to hear someone with a GX2/88/98 combo say, "Hey look, Leonardo, there is no production penalty with that combination!")

[Hgradio1]

It comes down to YMMV. There seems to be no set rule or list of a particular combo/mb/chipset/cpu etc to give a certain loss versus shader difference. In my case I just had to juggle the video cards around in my 5 rigs to get the best performance. I found that as a rule the least difference in shader count equaled the smallest decrease in ppd. Others may give different examples but you just need to see what your setup yields.

[toTOW]

From my personal experience (using WinXP) :

- mixing a 8800 GTS 512MB (128 SP) with a 9600 GT (64 SP) gave full performance from both GPUs
- mixing two 8800 GTS 512 MB (128SP) with two 9800 GT (112 SP) gave degraded performance from both GPUs.

Some people are having troubles mixing a GTX2xx with an older (8xxx or 9xxx) board ...

There is no rule to predict which combination will work and which won't, but the rule is to avoid mixing board with different numbers of SP, and from different generation.

[Leonardo]

Thanks, guys. I guess I'll be trying mix and match.

[MoneyGuyBK]

From my personal experience (using WinXP) :

.........Some people are having troubles mixing a GTX2xx with an older (8xxx or 9xxx) board ...

There is no rule to predict which combination will work and which won't, but the rule is to avoid mixing board with different numbers of SP, and from different generation.

*** I am running a 9800GX2 alongside a 8800Ultra with no issues.......






Peace

[toTOW]

So you're the exception that makes the rule true

As I posted above, I never find a way (except trying to do so) to predict if issue will be there or not ...

[Hgradio1]

Money, would you tell us your mb etc setup for the record ? Tnx

[MoneyGuyBK]

@ toTOW..... YOU are funny, my mom thinks I am.... I tend to disagree.....

@Hgradio1
MoBo = 780i EVGA
Cards = All EVGA 9800GX2
CPU = Q6600 at 3.2-3.4 Ghz depending on the season










Peace

[Leonardo]

*** I am running a 9800GX2 alongside a 8800Ultra with no issues.......

So you're the exception that makes the rule true

The GX2's GPUs and the 88 Ultra's GPU all are 128 stream processor architecture - same GPUs. So it's no coincidence that there are no driver/OS/motherboard (whatever) mishandling.

[toTOW]

Good point Leonardo .. I though MoneyGuyBK was talking about 8800GT, but it is the Ultra one

[Leonardo]

Yesterday I installed my new acquisition, my latest 9800GX2. It runs just fine and ran well side by side with a 9800GT. As is reported by others though, not all three GPu cores would fully process. No matter the physical configuration of the cards in the case, one out three GPU2 unit's production would always fall off by about 1000PPD. So...I pulled another GX2 out another Folding box and matched it up with this latest. This box now has a quartet of G92 GPUs singing a fabulous song. It's working perfectly. The orphan 8800GT that came out of this rig went into the machine that lost the other 9800GT. All's well.

[sbinh]

Does anyone mix 9800gtx (or gtx+) with 8800gt card on same board?

When I put 8800gt (g92) along with 9800gtx (or 9800gtx+), 1 card can run with full score while the another can get only 1/2 of what it supposed to.
(ie: 8800gt should get 5k ppd, if mixing with 9800gtx, the 8800gt would only get 3k to 3.5k ppd)

if yours run fine, which drivers are you using?

[Leonardo]

The 8800GT and 9800GTX have a slightly different core. Respectively, the cards have 112 and 128 stream processors. Nvida cards don't work too well in the same computer under GPU2 Folding if they have different stream processor counts. Unfortunate, but true.

I'll trade you a 9800GT OC (MSI) for your GTX, if you are interested.

[sparky29]

I've got a 9800GTX+ and an 8800GS. The GS gets about 1/2 the points that it did when it was the only card in the system. Seems to be a problem mixing shaders. I wish I knew this before I bought the 9800, I would have been better off with two 8800's for less money. The 9800 will go in a new build when I get around to it, so I will just make sure to match shaders when I add secondary cards to both systems

I wonder if this is anything that can be fixed in the client, or is it strictly a hardware issue?