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HD4890 at PCI-E X2 not X16

Last response: in Graphics & Displays
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October 21, 2010 8:54:33 PM

Hi,
I ran into this problem about 6 months ago, tried to fix it failed and have just about given up.

I noticed a slight difference in my video fps while gaming so I did a benchmark with futuremark (03 I believe) and noticed about 5000 points missing. I then checked things out with CPU-G (?) and found that my graphic card was at X2 not X16 (PCI-Express version 2.0). So I opened up my case (turned everything off) and pulled the card out and reset it, just in case it had come loose or something. Back to X8 not quite X16 but better than X2. Tried resetting it again and it went down to X2 again. This began a series of bios resets, with and without pulling the battery out, resetting the card, cleaning every part imaginable until finally it ended up at X8 so I decided to leave it.
Of course I decided to clean the dust out of my case near the end of summer, pulling out all the cards etc. and it returned to X2 were it is now.
Any ideas... That's a HD4890 PCI-Express X16 card in a PCI-Express 2.0 slot running at X2 instead of X16. I've tried reinstalling the Bios, upgrading, downgrading the bios, newer video drivers, older video drivers, etc.
Here's my system
M3A76-CM motherboard bios version 1105
Athlon 2 X@ 245 at 2900mHz
4x1 GB Corsair XMS2 DDR2 800
HD4890 Vapor-X sapphire 2GB OC version (which I have not overclocked further)
Soundblaster 24bit 5.1 soundcard
OCZ 850watt gamersXstream powersupply

I don't know what else to add except I don't really know when (or what I did to that made) the problem start. I not sure how long after it started that I noticed it. And that when upgrading the bios from 8.01 to 10.04 CPU-Z recognised it as a 780G board and not a 760G board.

Any help would be really appreciated. Just to note the difference only seems noticable onthe most demanding games and even then it only seems like a slight trade of speed for quality

More about : hd4890 pci x16

November 5, 2010 2:45:38 AM

i cant believe no one answered you....well this happen to me....i reseted it like 100 times what it most likely is,is your bios is confused like mine..first make sure its up to date then take out your ram cards and put them back in and jump your bios thats the only way it worked for me..
November 5, 2010 3:07:44 AM

Hi,
Thanks for the reply,
I've tried the bios updates, and recently I removed my ram and reset it, (had to move the hard drives out.) I sort of think if I kept doing all this over and over eventually I might get it back to 8x or maybe even the great 16x but I've just spent too much time pulling that card out and putting it back in and trying different bios versions.
I did find some information on line about a PCI express bug ( that is basically my problem I think) but my motherboard only allows me to change two of the working solutions they give and neither of them helped.
You say, pulling the ram out and reinserting it helped (after a bios update ?) I might give that a try with the new bios they've released.
Thanks very much,
yeeyoh

and yeah I know no responses, pretty bleak huh...
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November 5, 2010 4:08:52 PM
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yeeyoh said:
Hi,
Thanks for the reply,
I've tried the bios updates, and recently I removed my ram and reset it, (had to move the hard drives out.) I sort of think if I kept doing all this over and over eventually I might get it back to 8x or maybe even the great 16x but I've just spent too much time pulling that card out and putting it back in and trying different bios versions.
I did find some information on line about a PCI express bug ( that is basically my problem I think) but my motherboard only allows me to change two of the working solutions they give and neither of them helped.
You say, pulling the ram out and reinserting it helped (after a bios update ?) I might give that a try with the new bios they've released.
Thanks very much,
yeeyoh

and yeah I know no responses, pretty bleak huh...




yes the said thing is this site is full of people with 30 years of computer knowledge and they had no clue or did not even care....but if you can get it to PCI-E x8 it really wont be much of a bottleneck...it only matters if you use over the memory on your card which in your case is 1GB...i dont know if you read it but here is a review showing the differences in between PCI-E frequencies( http://www.tomshardware.com/reviews/pci-express-scaling... ) theres lots of things you can do to get it back up to X16... i'll try to list them all



try running with just 1 ram card and see if it goes back up(you have 4 ram cards might need more voltage this happens alot)

try turning the voltage up very slowly on your ram cards(one + at a time and keep checking to see if it goes back up) make sure you don't fry them(or put them on there defult voltage mannely

try turning up your PCI-E frequency to 101-105 not much higher it could wreck your board

make sure you have the same type of ram cards(same cas latency same speed and same voltage)

if you have a overclock turn it off to see if it goes back up

i know you did this but take a can of air and spray it into the PCI-E slot
i tried all of these when this happen and i got mine back up to PCI-E X16 (my mobo is a asus m4a785-m)



i"m sorry if this does not help..really if it doesn't work.. demand asus to get it fixed because its 80% likely the board




November 12, 2010 12:22:25 AM

Hi,
I'll probably give your advice about the ram a try over the weekend. Right now I've got 4 1 GB sticks of DDR2800 corsair ram. The latencies are clocked lower than the SPD but still a little higher than what the sticks are rated for, and I've got the voltage overclocked by just a tiny bit .12 I think.
recently while trying to find a DVD media player that worked (to my liking) on windows 7 I notice that GPU-Z actually fluctuates with what is says my video card is doing. X2 with PCI-E 1.1 x2 with PCI-E 2.0, which has lead me to believe that my video card or my motherboard is using some sort of power saving feature. I know the video card's clock goes from 870 in 3D to 240 for 2D mode.
I know bench marking I've suffered no where near the hit I should be taking at x2 compared to x16. In 3D mark 03 for example my score when it held at x16 was 55000 (approx) and was at 48000 (approx) when I'd noticed it had shifted to x2. A drop in performance yes, but no where near what that article would make me think should happen if the card was really operating completely at x2.
I was going to post this power caving idea I had as a possible conclusion to this problem (for me at least) but since I'm not really sure I didn't feel comfortable doing it.
Anyway, having said all that, thanks for your help, I will probably try working at it from the ram angle (although I'm hesitant about messing with this board too much more and I'm possibly thinking of just hoping it will all hold together till I can get a motherboard that doesn't feel like it's falling apart. I think your choice of the m4a78 board over the m3a76 board was a very good idea I think I saved about $10 or $15 and all the bios' and updates seem to be for the 78 boards and they just send the same ones to the 76 boards eventhough the chipsets aren't the same)
Thanks again for the help,
yeeyoh
November 18, 2010 11:57:29 PM

Best answer selected by yeeyoh.
November 19, 2010 8:11:44 AM

This topic has been closed by Maziar
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