PCI-E 2.0 link @x8 on ASUS P7P55D Deluxe

Hello guys!

Since I bought this Asus P7P55D Deluxe, I have noticed an issue with PCI-E link using only one card in the first slot.

No matter what, the link is always x8. According to specifications, should be x16, since I'm only using one card, and the first slot.

I've tried 3 cards (one Nvidia and two ATI). With all of them, GPU-Z, Everest, and any other software, indicate x16 2.0 @ 2.0 x8.
The screenshots are with the Radeon 4870 and 5870. The results are the same.

I've tried everything and I am reaching the conclusion that it is a defective motherboard.

If there is someone with a machine like that, could report if something happens? If it is a combination of hardware and software?
Could anyone give a hint about what could cause this?

Config:
ASUS P7P55D Deluxe (BIOS 1408)
http://www.asus.com/product.aspx?P_I...Z35&templete=2

Intel Core i7-860
http://ark.intel.com/Product.aspx?id...ec-codes=SLBJJ

HIS Radeon HD5870
http://www.hisdigital.com/un/product2-473.shtml

Windows 7 Ultimate x64 (up-to-date)
Catalyst 10.3
Intel Chipset Drivers 9.1.1.1025

Below are some screenshots to illustrate the situation:
4870:
http://img684.imageshack.us/img684/9...nshottj.th.jpg

5870:
http://img580.imageshack.us/img580/8...nshot2h.th.jpg

There is no option to manage the PCI-E Link:
http://img191.imageshack.us/img191/1682/13042010.th.jpg

http://img191.imageshack.us/img191/5...010002a.th.jpg

I hope someone can help...

--
Diogenes

somewhat unrelated (since you have P55 board), but see this thread: http://www.xtremesystems.org/forums/...d.php?t=249130

are you running latest bios for your mobo?

I have pci-e speed problems too in my Asus P7P55D Deluxe mobo, i7-860 prosessor and Radeon HD 4870 combination.

When I warm reboot pci-e speed is almost every time x8 mode and when stressed (ie. game stop respondin and I have to force reboot) it could be x4 or even once it was x1. :shocked:
Drivers, bios and any other software not seem to have any impact in this issue of mine, IMHO it is somehow temperature related.
Every cold boot pci-e speed is ok. And comp.case open help too, even I got good ventilation in my case.

When I see my pci-e is ie. x8 I put PC to sleep for 10-20 sec, after that pci-e speed is correct x16.

@diogenesbr: Have you find out solution to your problem?

I have a p7p55d-e with a 8800gt (non deluxe variant and also 2nd gen p55), it is full speed pc-e 2.0 16x

Similar issue here:

I have 2x Nvidia GTX 660 (MSI Twin Frozr) on SLI setup, plugged onto an ASUS P7P55D-E EVO mobo.

One of the graphics cards operate on PCI-E x4 2.0 and the other on PCI-E x8 1.1 !!!

The mobo should support PCI-E @ x16 for single card configuration, or x8 for dual card configuration (SLI), according to the following:
http://www.asus.com/Motherboards/P7P...specifications

Is there any configuration option that would allow switching both PCI-E to x8 2.0?

Update:
Following some research for information on the web, I found an article (see below) suggesting that the Intel P55 chipset, which was used on many motherboards, limits the bandwidth of the PCI-E 2.0 bus down to 2.5GT/s per lane, hence providing the same bandwidth as PCI-E 1.0.

http://techreport.com/review/17513/i...xpress-chipset

The same issue is verified by another user, on an MSI p55-gd65 motherboard:
http://forums.anandtech.com/archive/...t-2228353.html

My understanding is that this is where the problem is. ASUS's web site and product documentation claims that the motherboard supports one of single PCI-E 2.0 x16 slot or dual PCI-E 2.0 slots at x8/x8 mode. GPU-Z measures half that: The actual performance of the PCI-E bus is PCI-E 1.0 x8 (i.e. half of PCI-E 2.0 x8), or PCI-E 2.0 x4 (i.e. half of PCI-E 2.0 x8).

I have informed ASUS technical support, requesting them to correct the documentation of their motherboards, to clearly specify the PCI-E performance that is supported by their boards.

Update (26/08/2013):

On 19 August 2013, I received the following response from ASUS:

"Thank you for your feedback, I am take your feedback to our relative department."

Very disappointing, really. They have not fixed the errors in the specs of the board. I used to be an ASUS customer for many years, from now on I will have to avoid them.


Attachment 131119

Attachment 131120

I know this is a reply to a 5 month old post, but I wanted to tell ntsarb that the PCI-Express Bus downclocks itself when not being used. Try clicking on the "?" and run the render test with the box NOT checked. You should see your bus speed change upward.

here is my GTX 680 on an Asus P7P55D-Deluxe with i7-860.

http://gpuz.techpowerup.com/14/01/19/6wd.png