Visual problems in games with Ti4600

[Ben]

I just upgraded from a GF2Ultra to a GF4 Ti4600. The card runs fast and I'm happy with the framerate. Unfortunately I've always had a strange effect in 3d games since the upgrade. It's going to be hard to explain without a picture, but imagine large distortions where the polygons meet at the corners. It's like a big-time reverse anti-aliasing. LOL! At the edges of shapes I see a strange blockiness that appears and disappears at random as I look around the room. It happens where two or more shapes meet. Sometimes I can even see through walls if I turn just right. Kinda useful for cheating but it looks like crap.

Anyway, it looks pretty crappy. At first I didn't complain too much because I just swapped cards and I figured it was a driver issue. Yesterday I got tired of it and wiped my OS drive. I did a fresh install of everything and the problem is still there, no change. I've tried several games. The problem doesn't seem to be tied to Direct 3D or OpenGL, I get the problem under both formats. I tried tweaking the vsync, on/off/auto, nothing helped. I tried turning on anti-aliasing and it made the problem a little worse.

I'm stumped here. Now that I did a fresh install I don't see what the problem could be other than faulty hardware. Has anyone else seen this problem?

Config: Leadtek GF4 Ti4600
Detonator 29.42 reference drivers
Direct X 8.1
Windows 2000 Pro SP3 (same with SP2 also)
MSI K7D Master with two MP1800's

 

[Ben]

Oh ya, temporarily tried the latest beta drivers on my old OS install before the format.

 

[Ben]

I wish we could post pictures, but since we can't here some link to screenshots. I've cropped or scaled these down from 1280x1024. Now that I look at the screenshots, the problem isn't as apparent. Believe me, it's 10 times more noticeable in the game itself because all these little corruption areas flash and scroll as you walk through the room.

shot of corner problem
another shot of corner problem
some strange window effects where the glass is showing through the pillars next to it

Here are some shots of a set of pillars that start out as two diagonal lines from far away and gradually turn into normal as you get closer
far away
closer
even closer
now they look normal

There are all from UT but I've seen the problem in almost every game. I'll try and snap some more shots from another game.

 

[Ben]

Anyone else having any problems like this?

Just upgraded to new 30.82 drivers and still same problem.

 

[BFG10K]

but imagine large distortions where the polygons meet at the corners.

The problems you speak of are known as Z buffering errors, caused by inaccurate or incomplete representation of pixels' depths.

These problems happen in a wide range of games to varying degrees and I haven't yet been able to figure out whether it's the drivers or whether it's a problem with the GF4 core. At this stage it looks more and more like the hardware is to blame as identical drivers on GF3 and GF2 chipsets do not produce the same errors. Some games are perfectly fine while others such as Serious Sam exhibit serious Z buffering artifacts where polygons at long ranges overlap and intersect each other.

To minimise the problem make sure that you run all of your games in full 32 bit mode and set your desktop to 32 bits as well. Also check your driver and game options and make you are using a full 24/8 bit Z/stencil buffer.

 

[Ben]

Cool, thanks for the feedback. If nothing else, it's nice to know I'm not the only one having the problem.

I'll double check my settings and set them to your recommendations.

It's kinda disappointing to pay the money that I did for this 4600 only to have it look the way it does. I'd almost prefer my GF2Ultra if there wasn't such a speed increase with the 4600.

I was hopefull that the new NVidia drivers were going to fix the problem, but they didn't.

 

[Ben]

mmmk, I feel like a dumbass now. The problems go away with 32-bit color. I coulda swore I tried that before but I guess not. Thanks BFG10K.

 

[ThreeEagles]

You bought a GF4 Ti4600 and you were running in 16-bit color?!?! ;D

 

[Ben]

Ya I know. What the hell's my problem? LOL!

 

[BFG10K]

That's very interesting that your problems vanish in 32 bit mode as I'm already in 32 bit mode and the problems are still there. Do you have Serious Sam 1 or 2? If so, run the Metropolis demo or the Cathedral/Valley demos and tell me if you see similar issues under OpenGL rendering.

Undying has minor Z issues while Serious Sam's are quite serious sometimes, although I have discovered that switching the game to Direct3D mode fixes the problem completely (although it does slow it down, naturally). That doesn't explain the issues in Undying but at least it proves that it's not a hardware problem.

So it could be three things:

(1) The games both have glitches (unlikely since I've seen them run just fine before).
(2) The drivers have glitches for those two specific games.
(3) There might be a setting in the games that is forcing a 16 bit Z buffer.

I'm definitely going to investigate this issue further.

 

[Ben]

OK, I guess I spoke too soon. The problem does go away in UT with 32-bit color, but other games are different.

Under SS and SS2 with OpenGL, 16bit or 32bit both show the problem. It isn't as bad as UT 16-bit but still noticeable. Like you said, the problem does go away by switching to Direct3D mode. I can't tell if it slows the game down or not. They both seem smooth. How do you pull up a FPS counter in SS?

Homeworld does it under both 16 and 32 bit using Direct3D. OpenGL doesn't work at all on Homeworld for some reason.

I don't have Undying so I can't test that one.

I play UT the most so that was my main concern but there still seems to be a problem here. With all the people using GF4's I'm surprised you and I are the only ones that noticed? Are we the only ones having the problem? I'm thinking about sending an email to NVidia with some screen shots and see what they have to say.

 

[BFG10K]

Under SS and SS2 with OpenGL, 16bit or 32bit both show the problem.

Very interesting as this effectively rules out my game settings (which I've double checked in the past) since you have the same problems as me. And I don't think it's the games because I never had any issues on my Ti500 so I guess that leaves the drivers when combined with a GF4 chipset to blame. Perhaps they are forcing a 16 bit Z in OpenGL mode? But that still doesn't explain why I have slight problems in Undying (Direct3D), unless that game is a genuine driver glitch and is unrelated to the widespread problem.

I can't tell if it slows the game down or not. They both seem smooth.

Yes, Direct3D is slower in Serious Sam but it fixes all of the Z buffering issues. In that mode it looks like my Ti500 did - perfect.

How do you pull up a FPS counter in SS?

/hud_iStats=1 shows you the framerate counter.
dem_bProfile=1 (then pick a demo) runs a timedemo and gives you the statistics for it.

Homeworld does it under both 16 and 32 bit using Direct3D.

Again, the results are even more puzzling as there is no discernible pattern for them, unless the drivers are doing something funky with all games in both APIs. But the strange thing is that some games are absolutely perfect.

With all the people using GF4's I'm surprised you and I are the only ones that noticed?

I'm usually very quick to spot things like this and I saw it immediately the first time I watched the Metropolis demo after I dropped my Ti4600 into my system.

Are we the only ones having the problem?

I highly doubt it. The other people just haven't noticed or simply don't care.