Production ??

[eaglescouter]

It's possible that your additional GPU load cannot be serviced by the CPU. Try reserving another cpu core for feeding the GPU's by reducing the SETI CPU count. Then watch the CPU activity levels to see if that core remains below 95% (indicating that it is able to keep up with the demand).

 

[The Wizard]

Hi !!

No, i'm using only 6 cores out of 8 for crunching.

The problem i think is that my mobo asus maximus extreme only
supports 2x16 pci slots at the same time. When adding the third card
that slot runs only in pci 8 x mode.
The mobo manual confirms this.
The odd thing is though thet when i ran 2 x gtx295's and my 560ti
the 295's ran at their max on all cores but the 560 only produced
25% of it's potential. GPU usage on the 560 showed around 80%...

Moving 1 gtx 295 out of the box and in another. Will only be running
2 cards in that machine. I'm a bit disappointed of myself for not doing
more research on that mobo before buying.

My next mobo, addidtion to the farm will be an EVGA X58 that can handle
3 cards without a problem.

Anyone have any experience with the x58 ?

The Wizard

 

[Eroc]

What Eaglescouter is recommending is to crunch less with the cpu so that they can feed the vid cards and keep them busy. Try reserving one or two more HT cores and crunch on 4 or 5 instead of 6 and see if that helps.

Edit: I recommend crunching on only 4 since you have 6 gpus. That sould be enough, though, many recommend 1 whole cpu core per gpu.

 

[FloridaBear]

My next mobo, addidtion to the farm will be an EVGA X58 that can handle
3 cards without a problem.

Anyone have any experience with the x58 ?

The Wizard

Yes, I'm running the X58 3xSLI board. I've never had 3 cards in there, but it had no problems with 2. Has been great for overclocking and has been very stable.

Keep in mind the cooling with 3 cards, as they will basically be adjacent to each other. It's going to get warm in there.

 

[Eroc]

Another thing about the 560 is architecture. I noticed my 460 running around 80% or less when running one instance. This is caused by the gf104/gf114 (460 and 560 cores). They don't always utilize all cuda cores due to ILP (instruction level parallelism). It can execute 3 simultaneous instructions as long as the third does not require either of the other 2 instructions first. So the third instruction set will at times sit idle. If you run two gpu units at a time it is more likely to utilize that third instruction set and gpu usage will be closer to 100%. I saw this in my gtx460 and I bet you too wiil see it in your gtx560 as well.

 

[Team kizb]

@ The Wizard

Which motherboard are you using [4] NVIDIA GeForce GTX 295's & i7-2600K?

Are all four slots running at 16x? If not, what speeds are the slots running at?

Either way, it seems to be doing have well!