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PCI-E forced to x1.

Last response: in Motherboards
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August 12, 2009 1:22:11 AM

Hi, I seem to have a problem with my motherboard. It seems as if the PCI-E 2.0 slot has been throttled down to x1 instead of x16. I first noticed this by poor Windows Experience Index scores and slow FPS.

At first I thought it was the graphics card, so I tested my old 8800GT, which seemed to be okay (which I have since sold), but the problem still exists with my second GTX 275.

My computer specs are as follows.
Biostar Tpower i45 clear CMOS,
Intel E8400 @ Stock,
Corsair Dominator PC2-8400 1066MHz DDR2,
Be Quiet 650W PSU,
XFX Nvidia GTX 275 XXX.

Of course this is slowing down my GPU meaning that I can't play games at my native res (1920x1080). I have tried the follow with no luck.

1. Clear the CMOS.
2. Adjust the PCI-E frequency to 101 and kept incrementing to 104 until the system refused to boot.
3. Flashed the BIOS.
4. Installed and reinstalled graphics and chipset drivers numerous times with uninstalls and reboots between.
5. Adjusted the Northbridge voltage to 1.45v.
6. Restored default values inside the BIOS.
7. Looked in the whole of BIOS for option to "Force PEG X1" or something similar.
8. Cleaned the PCI-E slot.
9. Added extra power to the PCI-E slots by using the aux power molex connection.
10. Checked PCI-E power connections at the graphics card and power supply end.

Nothing has worked so far.

Before you ask I have got the graphics card installed in the correct slot, I have checked all jumpers to do with graphics and crossfire on the Biostar and they are all in the normal position to give the first slot full x16.

I have had the exact same problem with a Palit GTX 275 which I RMA'd and I am now running a different graphics card (still a GTX 275) from a different supplier.

I am running Windows 7 RC1, which could be an issue. I can supply a link to my thread on the bit-tech forms so that may be some use. I have also attached a GPU-Z screenshot of my current graphics card, but I don't have one for the 8800GT, sorry. Other screenshots of Windows Experience Index scores and CPU-Z screens can been seen below as well. But please be aware that I'm not longer overclocked to 4GHz due to a CMOS clear.

Also both GPU-Z and Nvidia control panel says the card is functioning at 1x, but I don't have a screen shot of the latter. So any suggestions?











- Thanks bigboss

More about : pci forced

a b V Motherboard
a b U Graphics card
August 12, 2009 2:54:58 AM

First of all who told you to touch the PCI-E frequency??

Why would you have the Northbridge volts at 1.45v???

Son, do you know what your are doing in the first place????

:non: 
August 12, 2009 12:01:18 PM

I can find you about 10 places on Google where these are suggested methods of how to fix this poblem on the P45 chipset. I have a Northbridge cooler in place and Northdridges can easliy run at 1.5v safely for extended periods.

So the short answer is yes, I do know what I'm doing.
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a b V Motherboard
a b U Graphics card
August 12, 2009 4:53:55 PM

Well it looks like you do not know what you are doing since you do not need 1.45v On the NB if you are running @ stock speeds.... Leave it on Auto for now... dont overclock anything till you resolve this issue.....

THE PCI FREQUENCY should always be @ 100, you do not achieve anything by raising that particular frequency.....

An x16 slot does not throttle down to x1, that is a ridiculous statement....

The only thing that comes to my mind is that Win7 is not pushing the cards full bandwith due to a driver glitch, have you tried XP or Vista?







a c 80 V Motherboard
a b U Graphics card
August 12, 2009 8:03:10 PM

There's no need to talk down to the OP. This is actually a fairly common problem, regardless of what OvrClkr says. I had this problem with my motherboard while overclocking, but it was resolved by bumping up the Northbridge voltage a notch.

I'm sorry I don't have a suggestion on how to fix your problem, I just thought I'd let OvrClkr know he doesn't know everything there is to know about everything.
a b V Motherboard
a b U Graphics card
August 12, 2009 8:51:41 PM

Well shortstuff I think he tried that already and it didnt work, thats why I advised to leave the overclocking for later and try to get stability first.....

IMO it is ridiculuos to say that you need more than 1.45v on the NB to get a stable system at stock speeds.....
a c 80 V Motherboard
a b U Graphics card
August 12, 2009 8:55:46 PM

I'm aware that he already tried upping the Northbridge voltage. I was just letting you know that your statement about the PCI-E link speed dropping to x1 being "ridiculous" is absolutely not true.
OvrClkr said:
An x16 slot does not throttle down to x1, that is a ridiculous statement....
a b V Motherboard
a b U Graphics card
August 12, 2009 8:59:12 PM

Since when does an x16 slot throttle down to an x1?

School me please, i have never heard this happening to anyone in my 15+ years as an IT professional... I guess you learn something new every day......

a b V Motherboard
a b U Graphics card
August 12, 2009 9:03:28 PM

bigboss65 said:
I can find you about 10 places on Google where these are suggested methods of how to fix this poblem on the P45 chipset. I have a Northbridge cooler in place and Northdridges can easliy run at 1.5v safely for extended periods.

So the short answer is yes, I do know what I'm doing.


Im sorry, i didnt mean to be an A-Hole.....

I guess i posted at the wrong moment and it was totally my bad..... :( 
a c 80 V Motherboard
a b U Graphics card
August 12, 2009 9:07:10 PM

Like I said in my previous post, I've personally had my PCI-E link speed drop from 16x to 1x while overclocking.
a b V Motherboard
a b U Graphics card
August 12, 2009 9:13:01 PM

really..... never in my life I have heard of such a thing.....but I take your word, and like I said.. I apologize for being an a-hole.....

!