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PCIe x16 card running at only x8 (non SLI)

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Last response: in Graphics & Displays
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December 12, 2013 8:16:54 AM

Hi Guys,

I recently upgraded my system and while overclocking I suddenly noticed in CPUZ that my graphics card slot is only running at x8 instead of x16. The card in question is a recently bought
MSI GTX 760 gaming and is running at stock clocks. I have tried to use GPUZ rendering test but that doesnt do anything to the speed. The only thing I see change is the version changing from 1.1 to 2.0. As far as I know this board supports PCIe x 16 on all GPU slots and should I choose to run SLI then both cards would be running at x16

My full system specs are as follows

MSI Z77a-GD65 M/Board
i5 2500K CPU @ 4.4 currently
650W Super Flower 80 Plus Silver PSU
8GB DDR3 1600 Ballistix Sport Ram CL9 @ 9-9-9-24 1.5V (XMP)
256GB Crucial M4 SSD
2x 1TB WD Black HDD

I have not edited anything in the BIOS that could have changed something with regards to the GPU. The only I have seen that is related is PCIe 3.0 and that is set to Auto. I have not changed the GPU voltage and the only thing I have touched so far is the Turbo Multiplier, the Core Voltage of the CPU and switched off the C1E power saving features. In terms of BIOS pics I followed the first guy's pictures settings to a t except that I've lowered my multiplier to 44 in the hopes of slowly lowering my temps.

https://forum-en.msi.com/index.php?topic=159647.0

I have however followed another thread's suggestion by taking the card out and cleaning the contacts with Isopropyl alcohol and booting the machine without the card and then rebooting it after with the card. That didnt work either.

Should I somehow borrow a friends card and test it out? Should I reinstall drivers?

Any suggestions are welcome and appreciated!

Many Thanks!

Best solution

December 12, 2013 9:05:32 AM

Your MB has a PCIe 3.0 slot. The i5 2500K only supports PCIe 2.0. I think what you're seeing is your PCIe 3.0 16X slot running at PCIe 2.0 speeds(limited by the CPU) which would be PCIe 3.0 8x and not 16x.

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December 12, 2013 9:21:57 AM

+1 ss202sl

You'll need to upgrade to an Ivy Bridge CPU to fully utilize your PCIe slot
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December 14, 2013 9:29:36 AM

ss202sl said:
Your MB has a PCIe 3.0 slot. The i5 2500K only supports PCIe 2.0. I think what you're seeing is your PCIe 3.0 16X slot running at PCIe 2.0 speeds(limited by the CPU) which would be PCIe 3.0 8x and not 16x.



I get what you are trying to say and did some research myself but I'm still stumped as to why GPU Z is reporting that im running PCIe 2.0 x8 instead of x16. Since I'm limited by my CPU, shouldnt it downgrade to full speed (x16) PCIe 2.0? Is there a performance hit between PCIe 2.0 x8 versus x16? Thanks!

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December 16, 2013 9:53:28 AM

ss202sl said:
Your MB has a PCIe 3.0 slot. The i5 2500K only supports PCIe 2.0. I think what you're seeing is your PCIe 3.0 16X slot running at PCIe 2.0 speeds(limited by the CPU) which would be PCIe 3.0 8x and not 16x.



Correct :) 
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December 16, 2013 11:36:56 AM

gokul36 said:
ss202sl said:
Your MB has a PCIe 3.0 slot. The i5 2500K only supports PCIe 2.0. I think what you're seeing is your PCIe 3.0 16X slot running at PCIe 2.0 speeds(limited by the CPU) which would be PCIe 3.0 8x and not 16x.



Correct :) 


So GPU-Z is misreporting? Its actually running at PCIe 3.0 x8 = PCIe 2.0 x16?

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December 16, 2013 11:48:31 AM

Actually....In motherboard BIOS....... "PCI-E" Gen is set to "auto"....tats y......u PCI-E version changes
The Motherboard....wil automatically assign PCI_E based on GPU performance
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