Doom 3 framerate dips- unplayable, please help!

[888888]

This post is an extension of my post about AGP aperture size here:

https://www.videohelp.com/forum/viewtopic.php?t=253051

However, I decided that it would be a better idea to create a new thread to detail my in-game video problems rather than try to summarize them in that thread.

Anyway, here's my problem. I recently bought a new video card so I could do some 3D gaming. I did not want to spend $500 on a Radeon X800XT and was content with just getting playable framerates at lower detail settings. I bought a Gigabyte Radeon 9550 with 128 MB DDR memory and a 128 bit memory bus. From all the reviews I have read, I gathered that this card would be more than satisfactory for my needs.

Unfortunatly, there is a problem with performance in Doom 3. No matter how low I put the detail settings or resolution, the framerate takes a huge dip whenever there are enemies attacking on the screen.

For example, I try to play at 640x480 with LOW detail setting with all the advanced options off except bump mapping. VSync and Anti Aliasing are both off. I am then walking through hallways at 50 fps, and then a machine gunner jumps out and the game slows down to sub-10fps. Then I kill him and the framerate jumps back to normal.

I get about 43 fps in timedemo1 (third test run) at those settings but the timedemo is not indicative of my in-game performance and my typical Fraps benchmark is more like 25 fps. What is odd is that decreasing the resolution does not help performance. For example, I get the same timedemo1 scores at 1024x768 (desktop resolution) as I do at 640x480, and sometimes better. Lowering details and turning off advanced options helps but not by very much.

Like I said, I am not expecting much from the Radeon 9550 in Doom 3... but I am expecting it to be playable! The Radeon 9550 should be fully capable of running Doom 3 with medium detail at 640x480. Likewise with the processor, I understand the Sempron 2500+ is no powerhouse but I have read worse specs doing better in Doom 3.

I average 60 fps at 1024x768 with medium to high detail in Unreal Tournament 2004. I can run Serious Sam SE with similar results. I understand that these are much less demanding games than Doom 3 but I thought Doom 3 was supposed to be scalable for lower-end systems.

In case you don't feel like clicking on my system details, I have:

AMD Sempron 2500+
ASrock SiS 741GX motherboard
1024 MB PC2700 DDR memory- no errors with Memtest 86+
Samsung IDE Ultra ATA133 160 GB hard drive
Gigabyte Radeon 9550 128 MB 128 bit video card AGP 8x
350W PS
no overclocking on any system component

I am running Doom 3 v1.1 with Windows XP SP2.

Here are some things that I have tried to do to fix this problem:

-Every tweak I could find for Doom 3 including the doomconfig stuff and the unzipping of the .paks into the base folder. These "tweaks" only worsened performance.

-Installed newest ATI 4.12 Catalyst drivers from ATI. Installed older drivers that came with my card. Currently I am using newest Omega's 2.5.97a.

-Tried turning AGP fast-writes on and off in display properties and BIOS. Currently off.

-Disabled Radeon 9550 second monitor device.

-Defragmented all drives.

-Checked for IRQ conflicts (none).

Nothing has helped.

Here are some links to people on message boards who have been having similar problems such as myself:

http://www.computing.net/gaming/wwwboard/forum/2709.html

http://www.computerforum.com/archive/index.php/t-2555.html

http://www.computing.net/gaming/wwwboard/forum/2816.html

I thought I found some answers especially when I found something about disabling a scond monitor, but again nothing has helped.

And you know what really sucks, of the big three FPS games of 2004-(Far Cry, Doom 3, and Half Life 2), Doom 3 is the only one I like and would want to play all the way through.

I am about to go for my last option- reinstalling Windows, and updating my motherboard BIOS. If that doesn't help, I don't know what will.

Sorry about the super-long post. I like to give a lot of details so people can help me with my situation better.

Anyway, any sugestions? Thanks.

[thecoalman]

Don't know if this is the issue but I've read more than once that installing a video card over another can sometimes cause a lot of headaches.

[mattyboy]

I dont have time to read the novel you posted above , but fraps cause major slowdown, so dont use it and update your ATI drivers to at least 4.10, plus the 9550 isnt a very good card, youll need at least a 9800 pro to get good performance in doom3.
Trust me on this. Plus its a ram sponge, just like farcry and HL2 so having a 1 gb of ram makes a HUGE diff. HUGE!!!!

[mattyboy]

Don't know if this is the issue but I've read more than once that installing a video card over another can sometimes cause a lot of headaches.

Youll have to reinsatll windows, I didnt when I changed my 9800 pro to a n X800 and it caused slowdown and other issues. Reinstall windows with your new card and it should fix the problem, as long as you re not expecting too much out of your system

[Soopafresh]

Sempron 2500 ? I didn't know that chip was fast enough to surf the Internet, much less Doom.

Try these drivers - http://downloads.guru3d.com/download.php?id=24

[888888]

I appreciate you replying to my thread. However, maybe you should have read my thread because a lot of what you bring up I already covered.

but fraps cause major slowdown

Doom 3 is slow regardless of if I am using Fraps or the built in fps feature.

update your ATI drivers to at least 4.10

I have tried a variety of drivers including the latest official and unofficial ones.

youll need at least a 9800 pro to get good performance in doom3

At high detail settings yes, but at low detail settings NO. There are plenty of people enjoying Doom 3 on 9600s etc.

Plus its a ram sponge, just like farcry and HL2 so having a 1 gb of ram makes a HUGE diff. HUGE!!!!

I do have a GB of RAM. Why do you assume I don't?

Anyway, I think I will probably take your advice and reinstall Windows. Will have to do a lot of backing up beforehand though.