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x2 not x16 bus interface ??

recoil101

recoil101

recoil101

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Joined
8 Sep 2012
Posts
5
Hi, first off here's the relevant tech details about my rig :-

Motherboard - ASUS P6T Deluxe v1
CPU - Intel i7 2.67
Graphics - ATI Radeon HD 5970x2


The graphics card is a single card with dual GPUs on. The card is in the blue primary PCIe slot on the motherboard.

I've been experiencing sub par performance in games in relation to fps, and decided to do a bit of digging to try and find out why. When I used a diag tool to give me some more in depth info on the graphics card I was a bit surprised by the bus interface info.

To be specific the Bus Interface info is "The graphic card reports that it supports : PCI-Express x16 v2.0 it is currently running at PCI-Express x2 v2.0" on the first GPU and "The graphic card reports that it supports : PCI-Express x16 v2.0 it is currently running at PCI-Express x16 v2.0" on GPU 2.

gpu.png


Why only x2 and not x16 on the first GPU??? Is this to be expected??

I've had a look at the BIOS but can see very little PCIe configuration options. I've tried reseating the card with no change. I'll try it in the secondary PCIe slot (which the mobo manual states is also x16).


Am I just wrong to be scratching my head at this or is there something wrong with the pc somewhere???

Any help greatly appreciated!!
 
you have to stress the card and then look at gpu-z,it auto downclocks to x2 in powersaving and shoots up to 16x full load
 
Sorry, I should have mentioned that I ran the stress test (full screen) and it stayed at GPU1 2x, GPU2 16X. Left it running for a few mins and no change.

Thanks for the prompt replys!
 
Which pcie x16 slots are you using and do you have anyother pcie cards installed alongside your gpu's?
 
To Op is the FPS due to running modern games. I also own a couple of HD 5970s and the 1gb of vram per gpu can cause problems with some things.
 
Eddyr - Its in the PCIE_1 blue slot (described in the manual as the primary slot for a single graphics card). There are no other cards in the remaining PCIE slots.

Kaapstad - Yes mate, particularly Guild Wars 2. Getting 10 to 15 FPS a lot of the time which seems odd, I know it's not the most up to date 'uber' hardware.. but still...
Having said that, I'm certainly not alone in expecting higher FPS than Im getting in that particular game. I just wanted to be absolutely sure that there wasnt something wrong with my setup. A friend is running with an HD6970 (more up to date but a single gpu) and he's getting a solid 60 fps with ultra graphics. Sigh.... computers....
 
My mistake, I intially thought you had 2 dual gpu cards installed, nvm. I know some boards can have some bizarre lane splits particualriy with other slots taken up, but seems that's not the case.


It sounds like its an issue with the onboard pcie communication on the card itself if one of the gpu's is reporting full bandwith and the other only x2.
Can you disable one gpu and see how games fare without bottlenecked communication between the gpu's/gpu-system. Or whether disabling gpu2 results in full bandwith to gpu1?

edit: and are you sure the stress test is using both gpu cores? Perhaps gpu1 is staying in low power mode as only one core is being used.
 
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I've no idea how to disable a gpu unfortunately, can't see anything in catalyst about it.

I've run the render test and monitored the GPU useage. Gpu1 (at 2x) was running at around 95% and Gpu2 (at16x) was running at around 85%.
 
Neither do I unfortunately, just throwing out some shapes. I do recall reading about ppl disabling gpu's on dual gpu cards or at least running games on only one, if my mind isn't deceiving me. Maybe it was game specific or simply crossfired single gpu cards, hopefully someone else may know.
 
I don't think you can disable 1 gpu with a HD 5970, you can with nvidia cards but thats another story.

If you want to do a run in 3dmark11 or unigine heaven 3.0 benchmark at stock speeds 725/1000 and I will compare it with mine. Also if you use heaven 3.0 could you let me know what settings you use.
 
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