Enable triple-buffering or disable Vsync.

7900GT is not high end card but close. The high end is 7900GTX.

Cheers,

pentiumspeed wrote on 2023-02-12, 22:46:

7900GT is not high end card but close. The high end is 7900GTX.

Cheers,

if we must get boring, 7900gtx is enthusiast-level

The Serpent Rider wrote on 2023-02-12, 22:44:

Enable triple-buffering or disable Vsync.

Thanks for the suggestion, did it in CCC, no change.

Try some older drivers maybe.

You may also want to get something called UQE Doom3.

I never seen anyone recommend that. Dhewm3's usually the preferred yamagi-like analogue to maintained doom3 source ports and should provide no gratuitous new graphical effects (at least it restores carmack's reverse and should still have the ARB2 path)

Disable AA
Use High instead of Ultra
Look for any config tweaks for Doom 3 for radeon cards.
Try older or newer video drivers or OpenGL ICD versions.

If you want to try ports you can try:
fhDoom v1.5.2 1414 or older
Ultimate Quake Engine v132 (Modify MajorOS and Subsystem in header to 4.0)
dhewm3 v1.5.1pre1 (Modify MajorOS and Subsystem in header to 4.0)

Maybe the 1GB VRAM just isnt enough. Ultra settings wants 512MB texture memory and when you use 8xFSAA it really eats video memory on top of that.

leileilol wrote on 2023-02-13, 00:04:

I never seen anyone recommend that. Dhewm3's usually the preferred yamagi-like analogue to maintained doom3 source ports and should provide no gratuitous new graphical effects (at least it restores carmack's reverse and should still have the ARB2 path)

I don't really follow the ports. UQE only added widescreen resolutions and automatic FOV for those resolutions. I was tired of using the console to set custom resolutions hehe.

Yeah I would try without AA and see what happens. I don't know if 1GB RAM would be an issue though. I would definitely lean towards AMD driver backward compatibility quirks.

You can always use RivaTunerStatistics server (via MSI Afterburner) to see VRAM and GPU usage and other potential bottlenecks. Also stable 60fps are not possible on P4 3Ghz.

I got low FPS too while using an x1900xtx with a P4HT (a lot of stuttering too), when i switched to a core2duo my fps went up to 60\55 with everything maxed at 1280x1024.

I think it's the CPU and RAM combination, even though i tried lowering details, resolution and effects i could never get a stable framerate while using a P4.
You should experience a similar behavior in stalker and neverwinter nights 2, it was a stutter fest for me.

Thanks for all the suggestions, here is situation report:
All FPS numbers below are for thatsame scene with the corpses (Delta Lab) pictured on screenshot in OP.

Quick recap:
Catalyst 13.9, 1024x768/ Ultra / 8xFSAA = 21FPS.
Catalyst 13.9, 1024x768/ Ultra / noFSAA = 21FPS.
Catalyst 13.9, settings downgraded to 800x600 / Medium / noFSAA = 22FPS.
Catalyst downgraded to 11.4, lowest version supporting HD6670, settings are 800x600 / Medium / noFSAA = 16FPS.

Now I did mention that I'm comparing the 2 specific cards and while yes it's not precise 60fps in majority of scenes but rather a 50...60fps range during normal gameplay I don't consider it a showstopper. System is i915 2GB DDR2 btw.

Back to GF 7900GT, FW ver.93.71:
1024x768/ Ultra / 8xFSAA = 36FPS.
1024x768/ Ultra / noFSAA = 38FPS.
1024x768/ High / noFSAA = 38FPS.

I then went to kneecap the 7900GT to 450MHz core / 630MHz DRAM to see the effect.
1024x768/ High / noFSAA / downclocked = 37FPS.

So I see here little to no performance scaling depending on the GPU load.

I then saw this twitter conversation with John Carmack from 2012 mentioning a certain config variable on a similar card (HD5770) so I went to test it:
Catalyst 13.9, 1024x768/ Ultra / 8xFSAA / rs_enable "0" / r_skipPostProcess "1" = 21FPS.
Catalyst 13.9, 1024x768/ High / noFSAA / rs_enable "0" / r_skipPostProcess "1" = 22FPS.

Didn't work.

Info update,
The same Radeon HD6670 with the same driver ver. 13.9 was tested with a faster CPU (quad-core) and the FPS drop problem in that scene is gone.

1024x768, Ultra, 8xFSAA, tripple buffering, v-sync.

It appears that Doom 3 does something in software when ran on a Radeon unlike what happens with GeForce. At first I speculated it may be soft shadows but

1 r_shadows 0

didn't fix it.

I call CPU bottleneck and problem solved if you run any half-decent CPU.

Indeed it sounded like a bottleneck coming from the CPU, i couldn't racket my brain over the performance i had with a high end P4 HT and my GPU neither, fact is that P4s start struggling with decently demanding games from 2004 forward already; happy to hear you solved it.

I ran into this exact same issue with an Athlon 64 3800+, 2 GB of RAM, and an ATI X1900XTX. The game would run fine, until the framerate just nose-dived to 3 FPS during the intro section with the dropship even at 640x480 and Low detail. Downgrading to Catalyst 7.11 didn't solve the problem, nor did an un-install/re-install. I needed to delete all of the .cfg files in Doom 3\base; one set of files was left over from a previous install of the game and re-generating the configuration solved it completely. Now I can run at 1600x1200 at a near-locked 60 FPS at High detail (haven't bothered with Ultra yet, since it just doesn't use compressed textures compared to High), and thought it was worth posting the solution here for posterity. If one has a fast P4 or Athlon 64 system, it's probably not a CPU bottleneck!