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PCIe 2.1 card in 2.0 slot running at x8

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Anonymous
a b U Graphics card
October 19, 2011 11:13:31 PM

Hi Gang,
So I upgraded my motherboard from a 890GPA-UD3H (v.1, BIOS F9) to a Asus Sabertooth 990FX. I noticed when I installed my 5850 Black Edition ( a PCIE x16 2.1 card) into slot 1 (a PCIE x16 2.0 slot) I am having a problem. It seems my graphics card is running at x8 rather than full x16. I tested the slot with a older PCIE x16 2.0 graphics card (a 8800GTS 512) and it runs at full speed. I am thinking the issue is because the slot itself isn't 2.1 it has to run at a slightly reduced speed.

Does this logic make sense? Also, I did do some research and looking around before asking, so please no one pop up with a "search is your friend" or hot-link to a similar thread. I don't want to necro or hijack anyone else.

It seems AMD used PCIE x16 2.1 and Nvidia has stuck with 2.0 (for now, I hear 3.0 is coming soon.) I know the difference for a single card between x8 an x16 is about 2% performance lost. And this really isn't a big deal. I just want to make sure I am on the right track. I should note that I tried to overclock the pcie bus to 102 MHz, since I read it might fix the issue. No luck. Wiped my Win 7 install thinking it might be old drivers causing a conflict, and no luck. Upgraded video drivers, nothing. So I think this has to be running at x8 due to it's design as a 2.1 card in a 2.0 slot. Otherwise, I am at a loss. Maybe AMD did this as part of the way they will run SLI. Who knows.

Thanks for your help!

More about : pcie card slot running

a b U Graphics card
October 19, 2011 11:34:45 PM

the performance lost for a GTX480 is about 2%, for any card under that performance it's 0%. try updating the mobo BIOS

*your card is in the top most PCI-E slot, correct?
a b U Graphics card
October 19, 2011 11:49:35 PM

dirtyferret said:
the performance lost for a GTX480 is about 2%, for any card under that performance it's 0%. try updating the mobo BIOS

I believe that that applies to any card. Even a lower end card. From reviews and research I have done, it has shown that even high end cards get a @5 decrease.
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a b U Graphics card
October 20, 2011 12:40:13 AM

HostileDonut said:
I believe that that applies to any card. Even a lower end card. From reviews and research I have done, it has shown that even high end cards get a @5 decrease.


http://www.tomshardware.com/reviews/amd-crossfire-nvidi...

GTX 280 in single mode showed no difference from x16 or x8

ATI 5850 in CF showed 2% decrease but no single mode testing was done
a b U Graphics card
October 20, 2011 12:57:33 AM

what the hell are you talking about? you just took this whole topic to GTX580 vs GTX 480 in x8? No one brought that up, no one asked for it. No one said the either card would not work,..just WTF?
a b U Graphics card
October 20, 2011 1:00:01 AM

dirtyferret said:
what the hell are you talking about? you just took this whole topic to GTX580 vs GTX 480 in x8? No one brought that up, no one asked for it. No one said the either card would not work,..just WTF?

You said anything above a GTX 480 would get trouble I though. A GTX 580 is stronger than a GTX 480, but had absolutely no trouble at all in a an 8x slot. 8X is still fine. Above a GTX 480 you don't just start losing performance like crazy. Maybe we are misunderstanding each other. Not sure what. I think I am getting what you are saying.
a b U Graphics card
October 20, 2011 1:03:58 AM

i said any card under the GTX480 in performance. obviously the GTX580 is above and would have a similar issue as you stated above...you are arguing with yourself ;) 
a b U Graphics card
October 20, 2011 1:05:20 AM

dirtyferret said:
i said any card under the GTX480 in performance. obviously the GTX580 is above and would have a similar issue as you stated above...you are arguing with yourself ;) 

OH! Sorry! My mistake! Oopsies! :pt1cable: 
a c 169 U Graphics card
October 20, 2011 1:19:39 AM

guys, he just wants it running at its rated speed, which it should do regardless how many % he is losing. Try re-seating the card, i had this issue with my 6850, would run at 4x, then I re-seated it, and it went to 8x, then re-seated the sli selector and got 16x finally. And PCIE2.1 is the same speed as PCIE2.0. There are no pcie 2.1 motherboards that im aware of, only 2.1 gfx cards.
Anonymous
a b U Graphics card
October 20, 2011 1:35:30 AM

I've reseated the card a number of times. No difference. Also I'm on the newest BIOS. I am aware most AMD motherboards support 2.1, but as for these new 990FX boards, I am flying blind. Like I said, it seems like it was a sacrifice between supporting AMD's 2.1 or running SLI. I could be 100% wrong, but this would make sense to me as all modern cards are 2.0 for nvidia. And it seems that SLI on AMD is a major selling point for these boards anyhow.
a c 169 U Graphics card
October 20, 2011 5:36:09 AM

go into BIOS and reset everything to defaults.
Anonymous
a b U Graphics card
October 20, 2011 6:19:14 AM

Done, made no difference.
Anonymous
a b U Graphics card
October 20, 2011 8:38:08 AM

Just tested in Ubuntu 11.10, newest stable drivers from the repositories (11.8) and it reported back "Maximum Bus Settings : x16" so that tells me whatever the hell is going on, it's gonna be driver related. Not hardware. In Windows 7 on the drivers, version 11.10 Preview 3 the computer is reporting "Maximum Bus Settings x8" so I guess somehow the drivers with this motherboard aren't playing nice together. Very odd, but not surprising. AMD/ATI drivers have always left something to be desired.
a b U Graphics card
October 20, 2011 9:57:49 AM

Well, this is slightly different from what I experienced with my 2 5770's.....:) 
One would work at 8X and the second would work at 16X.... Same rig, same slot, same batch of cards , same Pcb rev, same BIOS .
It had me absolutely bewildered at the time, after trying all sorts of combinations and in multiple rigs under different OSes nothing seemed to change.
Finally, all I did to get the problem resolved as a last resort, I backed up the GPU Bios from the card that worked at 16X and flashed the damn thing onto the one that persisted to work at 8X....and .............. the crazy thing started working at 16X.
Funny, but , it did work..... and finally.
a c 169 U Graphics card
October 20, 2011 10:27:39 AM

"and it reported back "Maximum Bus Settings : x16" so that tells me" < that tells you the maximum bus speed of your motherboard, not what it is running at.
Sounds like alyoshka has the answer. you have tried everything else, maybe its a corrupt BIOS.
a b U Graphics card
October 20, 2011 10:37:10 AM

What makes you think it's running at 8X speed?
a b U Graphics card
October 20, 2011 10:38:09 AM

GPUz tells him so.... I think.
October 20, 2011 11:55:36 AM

@alyoshka, what application did you use to flash your GPUs BIOS?
a b U Graphics card
October 20, 2011 1:07:30 PM

I used GPUz to first backup the BIOS from one card.
And then used the Winflash utility.

But.... I must warn you, using all these programs is a tricky job. Go thru a tutorial first and be sure you have the Other old card your 8800 lying around at hands length.

Something like this will be helpful
http://www.techpowerup.com/printarticle.php?id=34
a b U Graphics card
October 20, 2011 1:24:01 PM

reseat the card
a b U Graphics card
October 20, 2011 1:26:23 PM

gnomio said:
reseat the card

Read first...
"I've reseated the card a number of times. No difference."
a b U Graphics card
October 20, 2011 1:29:17 PM

have you tried a different slot?
Use Sandra to see if CPU-Z reads it correctly
Anonymous
a b U Graphics card
October 21, 2011 7:36:57 AM

alyoshka said:
GPUz tells him so.... I think.

Correct. As I stated above, it's a driver issue. In Linux I run full speed (according to the AMD driver information). In Windows, 8x. I don't know why this is happening on my system, but I think it's something to do with 990FX and how it does things. I could be wrong, but I suspect I am right.
Anonymous
a b U Graphics card
October 21, 2011 7:37:39 AM

gnomio said:
have you tried a different slot?
Use Sandra to see if CPU-Z reads it correctly

I've tried all three PCIE x16 slots. No difference.
Anonymous
a b U Graphics card
October 23, 2011 4:17:09 PM

Flashed BIOS of the card for the exact same BIOS (same version number) hoping it would help. Nope. Swapped back to my old motherboard (this thing used to run at x16 on this board...) and no change. A thought, which is probably least likely of all, is that through some power saving option it's being throttled back in Windows? Maybe due to the fact I've downsized from a 22" 1080P monitor to a 19.5" 1440x900 monitor (has a higher refresh rate, and the 22" is pulling duty as a TV in my bedroom, thanks to my normal tv going out on us. Thankfully it has HDMI) and since it isn't pushing hard at all, it stays at x8? Does that sound possible?

In GPU-Z it's reporting, under Bus Interface, "PCI-E 2.0 x16 @ x8 2.0" so the card is reporting full speed is available, it's just being throttled for some reason. I am really at my wits end on this and I've asked for a RMA from XFX.

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a b U Graphics card
October 23, 2011 6:38:38 PM
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Quote:
Flashed BIOS of the card for the exact same BIOS (same version number) hoping it would help. Nope. Swapped back to my old motherboard (this thing used to run at x16 on this board...) and no change. A thought, which is probably least likely of all, is that through some power saving option it's being throttled back in Windows? Maybe due to the fact I've downsized from a 22" 1080P monitor to a 19.5" 1440x900 monitor (has a higher refresh rate, and the 22" is pulling duty as a TV in my bedroom, thanks to my normal tv going out on us. Thankfully it has HDMI) and since it isn't pushing hard at all, it stays at x8? Does that sound possible?

In GPU-Z it's reporting, under Bus Interface, "PCI-E 2.0 x16 @ x8 2.0" so the card is reporting full speed is available, it's just being throttled for some reason. I am really at my wits end on this and I've asked for a RMA from XFX.

Not nessessarily true, there can be PCI-E x16 slots that run at 16x, 8x, or 4x, period. So, just because it says 16x doesn't mean it runs at 16x. Also, it might just be read wrong. You could be running at full 16x, just it is reporting 8x for some reason. I watched a video on youtube once and the guy had a 16x or 8x 8x board and ran 2 GPUs. It reported 16x x8 when it was actually run 8x 8x.
Anonymous
a b U Graphics card
October 23, 2011 7:07:56 PM

HostileDonut said:
Not nessessarily true, there can be PCI-E x16 slots that run at 16x, 8x, or 4x, period. So, just because it says 16x doesn't mean it runs at 16x. Also, it might just be read wrong. You could be running at full 16x, just it is reporting 8x for some reason. I watched a video on youtube once and the guy had a 16x or 8x 8x board and ran 2 GPUs. It reported 16x x8 when it was actually run 8x 8x.


Maybe, and I am well aware of the different speeds, but both motherboards and all the slots I tried were x16 (and electrically x16 as well.) But at this point I am giving up. Either I am going to go for a GTX 550 Ti (since I am not gaming at high res any more) or just deal. I kind of want to go 550 Ti (preferably an Asus model) just so everything will be one brand when I rebuild. (with the exception of ram and CPU obviously).
Anonymous
a b U Graphics card
October 23, 2011 7:08:03 PM

Best answer selected by greeneman510.
a b U Graphics card
October 23, 2011 8:13:22 PM

The specs for your MOBO show it has 2 PCI-e slots in the details at newegg it shows it listed as 2 (x16 or x8, x8) --which means if just using the one slot it will run at x16 speed but if using both slots (even if you just put an x1 card in the slot) it will run at x8 on both slots -- so do you have anything in the 2nd slot or is it empty ? IF there is a card in the second slot the board will only run both slots at x8 -- The 2 slots actually split a single PCI-e x16 lane so if the slot has something in it that would explain things - if the second slot is empty then the MOBO may be sensing incorrectly and think a card is installed - perhaps look at the empty slot and see if something is in there causing a connection or try using the other slot to see if the slot you are using is the one that slows the connection speed to x8 (you may have to use the correct one of the slots if wanting full speed and the card may be in the wrong one right now.)
a c 271 U Graphics card
October 23, 2011 8:22:37 PM

This topic has been closed by Mousemonkey
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