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ppara5
Valued Contributor I
912 Views

DH67CL says video card is PCIe x8, vendor claims it is PCIe x16

This is not a warranty issue, just a curiosity.

I have a DH67CL with a Sandy Bridge processor that I am converting to W-10. Since the only Sandy Bridge graphics driver is a generic one from Microsoft, I bought an entry-level video card, XFX Radeon R7 240, to side-step the issue. WEI is 6.6/6.6 on W-7, so I think it's working as it should. This will not be a gaming PC. But there is a curiosity.

XFX's website does not state the PCI specification, other than PCIe 3.0. I assumed it was PCIe 3.0 x16, but when I installed the card and ran GPU-Z: at idle the slot is at PCIe 1.1 x8, but if I stress-test it, it climbs to PCIe 2.0 x8.

The moral so far: GPUs take snoozes to save power just like processors. I didn't know that.

When I look in BIOS, in two places -- the video page and the PCI slots page -- it is referenced as PCIe 2.0 x8. I really think the card is PCIe 3.0 x8, but the DH67CL negotiates it down to PCIe 2.0 x8.

XFX support told me that the card is PCIe 3.0 x16, but I don't believe it, though it really doesn't matter because an entry-level video card like the R7 240 cannot saturate PCIe 2.0 x8, let alone anything fatter.

All video options are set to their default values. Could the DH67CL be identifying the card wrong?

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6 Replies
n_scott_pearson
Super User Retired Employee
61 Views

Your board's chipset only supports PCIe 2.0, so operation is negotiated down to there.

...S

ppara5
Valued Contributor I
61 Views

I knew that much, but what about the card being identified as x8? Would the negotiation include staying in x8 to save power?

idata
Community Manager
61 Views

The board has the following add-in card connectors:

 

• PCI Express 2.0 x16: one PCI Express 2.0 x16 connector supporting simultaneous transfer speeds up to 8 GB/s of peak bandwidth per direction and up to 16 GB/s concurrent bandwidth.

 

• PCI Express 2.0 x1: two PCI Express 2.0 x1 connectors. The x1 interface supports simultaneous transfer speeds up to 2.5 Gb/s of peak bandwidth per direction and up to 5.0 Gb/s concurrent bandwidth.

 

 

After checking specifications of the XFX Radeon R7 240, this is up to x8.

 

 

http://xfxforce.com/en-us/products/amd-radeon-r7-200-series/amd-radeon-r7-240-core-edition-r7-240a-c... http://xfxforce.com/en-us/products/amd-radeon-r7-200-series/amd-radeon-r7-240-core-edition-r7-240a-c...

 

 

NOTE: This link is being offered for your convenience and should not be viewed as an endorsement by Intel of the content, products, or services offered there.

 

 

 

Allan.
n_scott_pearson
Super User Retired Employee
61 Views

Well, since your graphics card is plugged into the (one and only) PCIe x16 slot, I would have thought that the negotiated interface would have ended up being PCIe 2.0 x16.

Try displaying the information using a (smarter?) tool like AIDA64 and see what it says the interface actually is...

...S

ppara5
Valued Contributor I
61 Views

I'm so ticked. I read that webpage before I posted my question, but I only looked at SPECS, the logical place for a technical tidbit like that. But on the FEATURES page, it clearly states "PCI Express 3.0 x8 bus interface." So PCIe negotiation only works between PCIe 2.0 and PCIe 3.0. Thanks for the homework.

ppara5
Valued Contributor I
61 Views

I tried AIDA64 Extreme and now I know why you recommend it. It's an encyclopedia of PC data. It verified that the board slot is x16, but I did not see any place where the card width was specified, but then again my eyes glazed over after reading a few thousand lines.

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