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-   -   7900 GS performance issues (http://www.nvnews.net/vbulletin/showthread.php?t=88773)

lambesk 03-26-07 11:36 PM

7900 GS performance issues
Hello. I'm currently running Kubuntu 7.04 beta, but my problems go back even to when I had Ubuntu 6.10 installed. I've tried 64-bit and 32-bit OS'es and drivers, but I'm having some serious issues. I also looked through as many forum threads as I could find, but I still don't have any answers as to why my performance has dropped so significantly with this new 7900 GS installed. The only article that may have shed some light is the following one that says XGL isn't supported with the 7900 GS. If that's the problem, any time frame on when it will be fixed? Anyway, here's that article.


As for my video problems, my computer specs have remained the same except for three upgrades. My previous hardware components where a Pentium 4 3.06 GHz on an Intel 845PE chipset motherboard and an AGP 6800 GT. My new hardware is a Pentium D 2.66 GHz on a VIA PT880 Pro/Ultra chipset motherboard and a PCI-E 7900 GS. In the first configuration, I would get roughly 52 fps in Doom 3 under linux and about 53 or 54 fps under windows. In my new configuration, I get around 53 fps under linux (on a clean install btw) and about 70 fps under windows! I am at a total loss as to why my performance has taken such a drastic hit. I even enabled the coolbits option and sure enough, my card is running at the appropriate speed. If it'll help, here's my xorg.conf file that the nvidia-xconfig program made.

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig: version 1.0 (buildmeister@builder3) Mon Feb 26 23:38:46 PST 2007

# nvidia-settings: X configuration file generated by nvidia-settings
# nvidia-settings: version 1.0 (buildmeister@builder3) Mon Feb 26 23:39:38 PST 2007

Section "ServerLayout"
Identifier "Layout0"
Screen 0 "Screen0" 0 0
InputDevice "Keyboard0" "CoreKeyboard"
InputDevice "Mouse0" "CorePointer"

Section "Files"
RgbPath "/usr/X11R6/lib/X11/rgb"

Section "Module"
Load "dbe"
Load "extmod"
Load "type1"
Load "freetype"
Load "glx"

Section "ServerFlags"
Option "Xinerama" "0"

Section "InputDevice"

# generated from default
Identifier "Mouse0"
Driver "mouse"
Option "Protocol" "auto"
Option "Device" "/dev/psaux"
Option "Emulate3Buttons" "no"
Option "ZAxisMapping" "4 5"

Section "InputDevice"

# generated from default
Identifier "Keyboard0"
Driver "kbd"

Section "Monitor"

# HorizSync source: edid, VertRefresh source: edid
Identifier "Monitor0"
VendorName "Unknown"
ModelName "Mag InnoVision"
HorizSync 30.0 - 86.0
VertRefresh 50.0 - 160.0
Option "DPMS"

Section "Device"
Identifier "Videocard0"
Driver "nvidia"
VendorName "NVIDIA Corporation"
BoardName "GeForce 7900 GS"

Section "Screen"
Identifier "Screen0"
Device "Videocard0"
Monitor "Monitor0"
DefaultDepth 24
Option "metamodes" "1280x1024_75 +0+0; 800x600 +0+0; 640x480 +0+0"
Option "Coolbits" "1"
SubSection "Display"
Depth 24
Modes "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"

Please help me out with this if at all possible. I really would like to get my video card performing up to par under linux, but I have no idea what's going on. I even checked all the libGL.so and libGLcore.so files, and everything appears to check out correctly. I'm currently using the 9755 drivers, but even rolling back to the 9746 drivers resulted in the same results. Thanks for any help you can give me.

netllama 03-27-07 10:37 AM

Re: 7900 GS performance issues

lambesk 03-27-07 04:28 PM

Re: 7900 GS performance issues
1 Attachment(s)
Hopefully you were requesting that I post a copy of the bug report. If so, here you go. As for looking at other threads, I have tried to do that and nothing seems to either match the same problem I'm having or have any resolution at present. Thanks for any help.

netllama 03-27-07 04:36 PM

Re: 7900 GS performance issues
Can you clarify where the performance drop is? According to your description the performance has either remained the same or improved.

lambesk 03-27-07 05:34 PM

Re: 7900 GS performance issues
Sure, I can try and explain it again. My previous CPU was a P4 3.06 GHz and my video card was an AGP 6800 GT. In Doom 3 in particular, I would get 52 fps using the built-in timedemo. With that same hardware under windows, I would get around 54 fps or so. As you can see, performance was pretty close. Here is where my problem lies. I upgraded to a Pentium D 2.66 GHz processor and a PCI-E 7900 GS. All of the other hardware (except motherboard) is the same. The cpu and video card are obviously superior, however, my performance under linux is usually in the 49 to 53 fps range and it will only hit 53 when I overclock my CPU to 2.9 GHz. This same hardware under windows will pull in 70.5 fps! We're talking over 15 fps difference now whereas previously the difference in performance was only about 2 or 3 fps at the most.

If I were to reinstall the AGP 6800 GT, I guarantee my performance would be higher than the 7900 GS, and that's just not right. There's no way a slower video card with less pixel pipes and core speed amongst other factors should be performing better under linux. I'm no linux guru by any stretch of the imagination, so if there's any more detailed info that I can give you, I'll be happy to do so. I just don't know where to go looking other than the xorg.conf and the bug report log. This is a clean install of linux and no resident information from my previous video card remains. Thanks.

P.S. -- my motherboard is a bit special in that it can support both AGP and PCI-E, but the PCI-E is electrically limited to 4x speed, but that's the same AGP speed my 6800 GT was running at.

netllama 03-27-07 05:42 PM

Re: 7900 GS performance issues
PCI-E x4 is not the same speed as AGP 4x.

Have you actually reinstalled the 6800GT to verify that the performance is higher?

lambesk 03-27-07 07:45 PM

Re: 7900 GS performance issues
Ok, I reinstalled the 6800GT and tested both video cards out with the same 9755 32-bit drivers. I received 54.1 fps at AGP 4x and 54.5 fps at AGP 8x with the 6800 GT. Just a gee wiz thing there with the difference in 4x/8x speed. Anyway, I have the 7900 GS reinstalled now and I got 54.6 fps with it. I might have got a slight increase on the 7900 due to enabling AGP fast writes, but I don't understand why that would be. Either way, you can see that the performance with the two video cards is identical for all intents and purposes. Is this normal under linux? Certainly that isn't the case. Any more info you could use? I have the xorg.conf and nvidia-bug-report from the 6800 if that would be of any use.

*EDIT* -- Just thought of something. I just installed some updated xserver-xorg-dev files and whatnot today for Kubuntu 7.04 before playing musical video cards. That could be what gave me a slight performance boost with the 7900.

netllama 03-27-07 09:10 PM

Re: 7900 GS performance issues
Did you test performance in the new motherboard with the 6800 card as well?
Its possible that you're hitting some kind of motherboard kernel driver issue.

lambesk 03-27-07 09:43 PM

Re: 7900 GS performance issues
My last post was all on the same motherboard. The only difference between the tests now is the video card being used. Everything else is identical. As far as a motherboard kernel issue, I have absolutely no idea how to check that. I can tell you what chipset I'm using, but I don't know much about building linux kernels or how to configure them. I'm running a VIA PT880 Pro/Ultra. Does that help any?

mooninite 03-28-07 12:49 AM

Re: 7900 GS performance issues
hm. can't delete messages! :O

lambesk 03-31-07 03:59 PM

Re: 7900 GS performance issues
I was going to put this issue to bed, but I accidentally stumbled upon something very interesting. You see, I was going to write everything off as a possible linux kernel issue. Just to sate my curiosity however, I decided to install the linux version of Quake 4 and benchmark it as well. Since it's based off of the Doom 3 engine, I expected the scores to be abysmal, right? Wrong! Here were my Quake 4 settings when I noticed something was up...

1280x1024, High Quality, 2x AA, SMP enabled --> 61.71 fps

Seeing that, I was a bit shocked. Those same settings under Doom 3 (minus SMP) gave me 55.2 fps. That's right. Quake 4 was outperforming the supposedly less intensive Doom 3. Here are the side by side scores for Quake 4 on Windows vs. Linux.

Windows, 1280x1024, High Quality, 4x AA, SMP --> 57.77 fps
Linux, 1280x1024, High Quality, 4x AA, SMP ------> 56.66 fps

THAT is the kind of performance that I'm used to seeing. Linux being within one or two fps of windows performance. To further test my theory, I did a slight overclock on my 7900 GS. 510 core/700 memory. Doom 3 performance DROPPED from 55.2 fps with 2x AA to 53.8 fps! Predictably, Quake 4 performance went up to 57.20 fps with 4x AA. These two programs are really the only things I have to benchmark linux performance, but it is apparent now that there is an issue there with Doom 3. I'm not certain if it's just the linux version of Doom 3 not working well with my motherboard or if it's the nvidia drivers. Personally, I'd bet on Doom 3 being buggered up.

Sorry to bother you with all of my troubles netllama, but I'm happy knowing that my 7900 GS is performing up to specs after all. Guess I'm down to just one reliable 3d benchmark in linux now, but that's not so bad I guess. Thanks for your help. Take care. :)

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