Background (The Why?)

I'm using AMD Graphics Cards for distributed GPU computing. BOINC, Folding-at-Home, and similar.

The Problem

I've replaced my old card, an R7 260x, with a much more powerful R9 270x. For my application, both cards could co-exist on the same board, but at this point in time, I'm just trying to get one of them working.

After installing the new R9 270x, I found performance to be slightly less than the R7 260x that was being replaced. To ensure that this wasn't just in my head, I pulled up 3D mark, and found that I was in fact scoring nearly 1500 points bellow the old R7 260x.

I figured that I had done something wrong during the install, so I proceeded to do the following:

  • Uninstall all existing AMD drivers
  • Re-install all AMD drivers
  • Update the BIOS
  • Reset the BIOS to it's defaults
  • Checked the power supply and the GPU's connections. (Corsair CX 750)
  • Checked to be sure that the GPU was seated in the correct PCI 3.0x slot.

None of these worked. Just to be sure, I left the configuration the same, and put the 260x back. Lo and behold, my old card also suffered a 50% performance loss. My 3D mark score was nearly halved with my old card as well.

I'm rulling out defective cards on this one, since I have two of them to test with. What surprised me is that now the old one isn't working properly.

I'm currently running memtest to see if its a memory issue, but since the problem didn't occur until I swapped GPUs, I'm thinking that the problems not that.

I'd also suspect the PSU, if it weren't for the fact that the R7 260x is also effected, despite using much less power than the R9 270x.

I'm honestly stumped at what this could be. The only reason I'm asking here is due to the genuine weirdness of the problem.

I do have a GT 730 Nvidia card (which is powered off the motherboard), that I can use as a control. I'm testing it now (If it is also slow, I can rule out the PSU)

  • Motherboard: Gigabyte GA-F2A88XM-D3H
  • Memory: Kingston Hyper X Fury
  • Black 16 GB (4x4 modules)
  • GPU(s): XFX Double-D Editon R7 260x and R9 270x
  • PSU: Corsair CX 750 HDD: WD 1TB x 3 in Raid 5
  • maybe you stressed the psu and damaged it. – Moab May 29 '15 at 4:32
  • Is it possible that the issue arose before installing the new card? Did you do a performance check on the old card immediately before installing the new one? – Paul May 29 '15 at 4:48
  • Unfortunately I didn't. That said, the memory checks out, and the unpowered GT 730 is unaffected. I'm going to use a meter on the PSU next. – Astor139 May 29 '15 at 10:52

Having tested a Motherboard powered GT 730, and confirming that it works, I connected a meter to my PSU. It was indeed not providing sufficient power. Replaced it under warranty, and everything is now working.

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