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multi GPU config

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Joined
20 Apr 2011
Posts
231
Location
Stoke on Trent
Hello All

This problem is really bugging me, and i have google for days to find the answer (+ posted in the software section on OCuk) but to no avail.
I am beginning to think what i want to do is not possible, but that makes multi GPU's pointless.
I would be very grateful of any advice!

I have a:
GPU 1: HD6970 (powering the "main display"/desktop)
GPU 2: Nvidia Quadro 4000

Both have the correct drivers (up to date) and are both detected by windows 7 fine (and afterBurner detects them both fine). Both have up to date BIOS.

I have 3 monitors :
Monitor 1 & 2 are connected to the HD6970 (HDMI)
Monitor 3 is connected to the Nvidia 4000 (DVI)

The Problem:
No matter what programme i run (inc furMark) and no mater what monitor i am using the only GPU that is being used is the HD6970 (the one the "main display" is connected to). This is seen in AfterBurner, as the HD6970 clocks up to its max as it should, yet even if i have furmark (or photoshop or anything else) open on monitor 3, the Nvidia always sits at idle
(if i keep swapping windows from monitors (fast) the Nvidia will clock up, so i know it works OK, but it soon clocks back down...+ if i only run this card, it works fine too)

If i change the "main display" (from Display Properties) to monitor 3, this then causes the whole system to uses ONLY the Nvidia GPU (again no mater what monitor i use or programme). So the same as before, but with GPU 2.

I have swapped the "detection" order of the GPUs in the BIOS, and also tried putting the GPUs in the opposite PCIe slots. this makes no difference. (the bios loading screen always appears on monitor 3 (connected to NVIDIA))

Google tells me to open up Nvidia Control Panel and "says" i can select the GPU to use per application. BUT Nvidia Control Panel does not detect/list the AMD card and does not offer any options to set a GPU per application anyhow...
(AMD control panel (CCC) does detect/list the Nvidia card on monitor 3, but does not allow the setting of GPU to use per application).

In addition, Photoshop will only let me use the GPU that is connected to the "main display" (under Photoshop>options>performance, it only detects 1 GPU, whichever is the "main display" )

Ideally what i would like, and have had working in the past under windows 7 (using the HD6970 and onboard Nvidia) is: for what ever monitor is being used to use the GPU that it is connected to...

So from what i can see, the second GPU is useless, and only really acting as a place to plug in a monitor... (this could have been done with a "active splitter" and 1 GPU). I cant see this being correct :-(

Surely it must be possible to use 2 GPU's and get the power of both at the same time? depending on what monitor is being used.

Another "quirk" and possibly connected.
I keep getting windows telling me and auto disabling the windows Aero Theme, stating i am running low on memory (i have 29GB (all detected and available).... + i have 16 Xeon threads). This happens randomly while only with Chrome or something else that is low power running (just done it, while typing this message...). Basically the whole system is on tickover, the GPUS are in "low clock mode", yet windows thinks it is low on memory :-(
(the RAM is NOT matched, i wonder if this is part of the problem, although it works fine...)

I have a DELL t5500 with the most up-to-date drivers and BOIS.

Any advice on this would be very much appreciated!!!!!!
(FYI: i am not a novice on a PC!! have built and fixed 100's (possibly more), code PC's/Servers for a living, yet can not fix this issue/bug/annoyance, so need a true grand master i think... who i will happily bow down to!)
 
I would love to know if this is possible for me utilising the best card for the job!

same here.... i would have thought the Quadro card is better for photoshop than a gaming card (maybe not, but it would me nice to be able to test this either way).
Basically i have 1 GPU and a small Nvidia Quadro heater :-)
 
what applications are you trying to make use the other gpu? Some apps allow you to select which adapter it uses for rendering etc.
 
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