How to boost your Doom3 performance by 40% on ATI hardware

Based on all the reports and screenshots of artifacting ATI's shader replacement code causes, it looks like setting filtering to straight bilinear & reducing AF level is a better performance tweak, as it does not create the standout artifacts ati's shader replacement code does.

 

IQ loss doesn't matter much to ATI though, does it? Just the point of having to alter the shaders of a game to get it to run acceptable on not just one card, but an entire line of cards, shows a lack of good OGL drivers/support. Sure ATI makes a fast card, but they aren't as fast in OGL as Nvidia, PERIOD. New drivers will help, but at the current time, not as good.

 

My results:

X800XT-PE (540/571)
P4-3.0GHz
1GB

DOOM3 BENCHMARKS - ULTRA Mode, VSYNC = OFF, 16xAF
36.3 - 1600 x 1200 x 32 x 2AA

DOOM3 BENCHMARKS - ULTRA Mode, VSYNC = OFF, 16xAF, Humus tweaked code
43.8 - 1600 x 1200 x 32 x 2AA

HOWEVER, when I ran the same before/after tests with HQ mode, I got the following:

DOOM3 BENCHMARKS - HQ Mode, VSYNC = OFF, 8xAF
45.9 - 1600 x 1200 x 32 x 2AA

DOOM3 BENCHMARKS - HQ Mode, VSYNC = OFF, 8xAF, Humus tweaked code
45.7 - 1600 x 1200 x 32 x 2AA

So it's a bit strange. I also notice the "white line" artifacting with the Humus code.

 

Are you referring to this?

 

Well, ATI made a huge stink about shader replacement & optimizations that affect IQ when Nvidia did it with the FX5900 series, its pretty humorous & hypocritical that ATI now releases shader replacement code on a public forum that reduces IQ and introduces artifacting for performance increase since they are behind with the X800 series. Probably an attempt to soften a blow, but not one they can do officially due to the significant IQ loss it causes - uninformed people would think their card is defective seeing the types of artifacts this new shader replacement code by ATI causes.

For ATI users, I'd just lay off the resolution and AF/filtering, at least you won't get the type of odd, standout artifacting ati's shader replacement code causes (which btw is far worse than anything I've ever seen with Nvidia's FX5900 shader replacements)

 

THEN why do the shaders look completely different on the outlines of walls etc. This is considered IQ loss for a FPS gain right?

 

Well ati hasn't released anything . Humus did on his personal time.

Don't make shit up .

Also note that not everyone has the iq problems.

These problems can be the result of other tweaks done in conjunction with this .

I used it on a fresh install and have no artifacting

 

You are completely out of line.

Tweaking the shader has nothing to do with how good or bad the Driver is. It is actually an indication that the Shader is programed to serve the needs of Nvidias Hardware (not driver). ATi's HARDWARE is faster at math. therefor making a change to rely more on MATH than fillrate increases porformance.

 

for those with really white specs like on page 4 of the thread, make sure you edit this:

PARAM specExp = { 16, 0, 0, 0 };

to PARAM specExp = { 8, 0, 0, 0 };

That fixed my probs.

I gain upto 16 FPS in some areas compared to the old code on my X800xt,

8 inc. FPS in timedemo 1... Not bad.

 

....read humus' sig please. Just because he works for ati does NOT mean that this change is officially supported by ati. Imo with a little bit of work, this change could improve performance AND quality...just need more work on it.

This is an EXPERIMENT...if you dont like it, by all means, dont participate.

Thanks for your opinion =)

Oh, and to the people who are seeing these artifacts...what catalyst version are you running?

 

I think rather than Ati v nvidia this should be regarded as letting the person who bought the game have a bit more flexibility on the IQ / speed trade off.I also find it very interesting as well, I think Demirug is being too hard on himself.

It also allows the cunning JC to fly his rockets while the general public write the first patch for him for free ( joke ).

 

My guess as to why the whiteness is showing up at medium but not at high or ultra quality settings is because image_usenormalcompression "2" is set when on medium quality. If you switch this to 1, without humus's new shader code, you will notice a similar ugly whiteness to everything albeit on a much larger scale.

 

I think that some people are forgetting that this did not come from Ati. AFAIK Humus did some investigation on his own and saw a possible improvement. He even acknowledged that it had its problems, he did it to show that it could be done, and maby JC could get it to work properly.

Yes it is a grey area becuase Humus now works for Ati but to me this is in the spirit of this website, investigation and discussion about 3dhardware.
People shouldn't be saying all of a sudden that Ati is going nuts writing replacement shader code to improve performance in DOOM3 with an IQ loss.

 

This is wrong also..

ATi is not doing anything. People on Forums are doing it. Nvidia was replacing shaders via app detection on their own. They were also directly reducing percision or changing to FP to Fixed function whenever they could.

This shader change is nothing like that. It is simpy making better use of ATi's math engine. Thats all. No changes in percision or anything like that. The changes do not cause artifacting when done on a clean install with no other tweaks. Not all the changes in this thread are performance related. If you added Humus's BM enhancement you will get increased aliasing but a sharper image. Just adding the couple changes that increase performance should not have an impact on IQ.

One more time.. This is a PERSONAL CHOICE change to shaders offered by people on a FORUM. It has nothing at all to do with ATi at all.

 

Humus works for ATI. You think he'd risk his job releasing this without his boss's approval to the public? This is obviously a unofficial public forum release approved by ATI (Humus' boss, at the least). You don't mess with one of the best games of the year with an IQ-reducing tweak then release it without asking if its okay first when you work for the graphics card company that is behind. Humus could get fired if he did that.

Looks like you are in the minority:

from this thread:

from Rage3d:

etc... In all likelihood you just haven't played long enough to notice them yet.

 

CrunchTime:


Uh, READ THE THREAD. Start at page 1, then 2, then 3. Those first few discuss this in detail.

This replacement, as stated right from the start is INCOMPLETE.

It assumes a global "shininess" value of 16 for all objects. If your doors are shiny you can use 8 or 6 instead, but then things that should be extra glossy will be too dull.

A "real" version of this fix will have to be done by iD, where the proper value for each object is passed into the shader with a constant.

The current version is passed a texture with the data, this fix replaces the texture lookup with math.

This is not some official ATI patch/fix, it was an experiment to see if there could be a performance gain by replacing some texture fetches with math and make ATI cards perform better. (for r300 and up, and moreso with those that have lower bandwidth to core speed/pipe ratio).

The answer to that is yes, and yes especially with high levels of anisotropic filtering on.


This may also be highlighting a weakness in ATI's texturing (cache or other hardware; perhaps software/driver component).


One must separate the visual artifacts from the performance boost, they are not necessarily related.

 

Heh. I finished nightmare today .

I don't have any problems what so ever. Note I also use ultra quality and only have these tweaks done.



As for humus . If he does it on his own time it is not ati doing it.


Thats just like saying a ford worker shouldn't own a trans am . Because it may reflect bad on ford .

WHich is buillshit .

 

No, its like a worker at a ford dealer emailing all the owners of recent Mustangs on ways to speed up the car by altering the drivetrain. Yeh, it might speed them up, but it might cause other adverse effects and problems. Of course, the worker would be easily fired if he did not consult Ford before emailing owners this "tweak."

If Humus didn't consult his boss before releasing this, he could easily get canned, just like the Ford worker.

Based on your other posts in this forum, I'm calling BS on you not noticing the artifacts. Everyone who doesn't have a long history of posting pro-ATI/anti-Nvidia has noticed artifacts. Apparently by reducing the amount of specular it makes them less noticable, but of course that is reducing IQ right there.

Again, lowering filtering quality if probably the best bet for an ATI owner who doesn't want strange artifacting.

 

That is just ****

"Release it"

ITS A FORUM DISCUSSION.

Humus is not even a driver guy.... You are intionally Twisting this into something its not. I would appriciate it if you would just stop it. Its Ridiculous and irritating.

 

Lets riot until wavey dave does a feature on this and tests it for us.