Help ! GTX 980's (2) in the same box, PPD dropped like a rock

[Markfw]

So I have one 980 in a box. Hot about 350k ppd or so, maybe sometimes 400. Then I added a second one, and it only gets 200k ! And I have 8 threads, but set CPU to 4, to be sure I had plenty to drive the cards. And first card gets 283 ! So total not much more than one card. Should be 800k total.

NOT SLI-ed and not configured as SLI in nvidia control panel.

 

[TennesseeTony]

Strange. My only thought is that it may have to do with the number of PCIe lanes your motherboard is capable of, and if the 2nd card is stealing bandwidth from some other vital component, such as a M2 SSD or something.

 

[Markfw]

X58 Intel mobo with 2 PCIe slots. Question, it I added it to mySr2 mobo running ubuntu, would it need more software installs ? It took forever the first time, so I don't want to risk breaking it, but it sure has the PCI lanes for it !

The only problem there, is, my PSU is out of cords. I need to use my ax1200i PSU, but its already incompatible with my motherboard on the Intel X58, and this is dual X58, so ?

 

[Markfw]

OK, New plan.... Change out 4790 ax1200 with ax1200i, should work. Put ax1200 in SR2 box, and buy new copy of win 7. Put 2 GTX980's (matching pair) in SR2 box. Put original PSU back in X58 box. Put ax850 back in its original case.

After re-doing all boxes in my house, I have a winning setup... Crap what lot of work. and 2 more copies of win 7.

 

[Rudy Toody]

That's why I always get a really good computer case. I want one that will hold up well after I stuff it full of hundred-dollar bills.

 

[theAnimal]

Could it be due to the WU core type? I have recently been getting more core 18 and some of those have very low PPD compared to core 21.