Half-Life 2 Performance Benchmark Preview
by Anand Lal Shimpi on September 12, 2003 12:34 AM EST- Posted in
- GPUs
More on Mixed-Mode for NV3x
We briefly mentioned the Mixed Mode of operation for NV3x GPUs that Valve implemented in Half-Life 2, but there is much more to it than just a special NV3x code path. In fact, the mixed mode NV3x code path was really only intended for the GeForce FX 5900 Ultra (NV35). The mainstream FX chips (5200/5600) require a slightly different code path.
Here you can see the 40% performance boost NVIDIA gets from the special NV3x
code path.
The GeForce FX 5600 (NV31) uses a code path that is internally referred to as dx82; this path is a combination of DX9 (pixel shader 2.0) and DX8.1 (pixel shader 1.4) code, and thus, doesn't look as good as what you'll see on the 5900 Ultra.
Although the 5900 Ultra performs reasonably well with the special NV3x mixed mode path, the 5600 and 5200 cards do not perform well at all. Valve's recommendation to owners of 5600/5200 cards is to run the DX8 (pixel shader 1.4) code path in order to receive playable performance under Half-Life 2. The performance improvement gained by dropping to the DX8 code path is seen most on the GeForce FX 5200; although, there is a slight improvement on the 5600 as you can see below:
The sacrifices that you encounter by running either the mixed mode path or the DX8 path are obviously visual. The 5900 Ultra, running in mixed mode, will exhibit some banding effects as a result of a loss in precision (FP16 vs. FP32), but still looks good - just not as good as the full DX9 code path. There is a noticeable difference between this mixed mode and the dx82 mode, as well as the straight DX8 path. For example, you'll notice that shader effects on the water aren't as impressive as they are in the native DX9 path.
Are the visual tradeoffs perceptive? Yes. The native DX9 path clearly looks better than anything else, especially the DX8.0/8.1 modes.
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dvinnen - Friday, September 12, 2003 - link
#31: I know what I said. DX9 dosen't require 32 bit. It's not in the spec so you couldn't write shader that uses more than 24bit percision.XPgeek - Friday, September 12, 2003 - link
Well #26, if the next gen of games do need 32 bit precision, then the tides will once again be turned. and all these "my ATi is so faster than for nVidia" will have to just suck it up and buy another new card, whereas the GFFX's will still be plugging along. by then, who knows, maybe DX10 will support 32 bit precision on the nVidia cards better...btw, im still loading down my GF3 Ti500. so regardless, i will have crappy perf. but i also buy cards from the company i like, that being Gainward/Cardex nVidia based boards. no ATi for me, also no Intel for me. Why? bcuz its my choice. so it may be slower, whoopty-doo!
for all i know, HL2 could run for crap on AMD CPUs as well. so i'll be in good shape then with my XP2400+ and GF3
sorry, i know my opinions dont matter, but i put em here anyhow.
buy what you like, dont just follow the herd... unless you like having your face in everyones ass.
Anonymous User - Friday, September 12, 2003 - link
#28 Not 24bit, 32 bit.Anonymous User - Friday, September 12, 2003 - link
Yeah, like mentioned above, what about whether or not AA and AF were turned on in these tests? Do you talk about it somewhere in your article?I can't believe it's not mentioned since this site was the one that make a detailed (and excellent) presentation of the differences b/w ati and nvdia's AA and AF back in the day.
Strange your benchmarks appear to be silent on the matter. I assume they were both turned off.
Anonymous User - Friday, September 12, 2003 - link
>>thus need full 32-bit precision."<<Huh? Wha?
This is an interesting can of worms. So in the future months time, if ATI stick to 24bit, or cannot develop 32 bit precision, the tables will have reversed on the current situation - but even moreso because there would not be a work around (Or optimization).
Will ATI users in the future accuse Valve of sleeping with Nvidia because their cards cannot shade with 32-bit precision?
Will Nvidia users claim that ATI users are "non-compliant with directX 9"? Will ATI users respond that 24bit precision is the only acceptable standard Direct 9 standard, and that Valve are traitors?
Will Microsoft actually force manufacturers to bloody well wait and force them to follow the standard.
And finally, who did shoot Colonel Mustard in the Dining Room?
Questions, Questions.
dvinnen - Friday, September 12, 2003 - link
#26: It means it can't cheat and use 16 bit registries to do it and need a full 24bit. SO it would waste the rest of the registryAnonymous User - Friday, September 12, 2003 - link
#26 That was in reference to the fx cards. They can do 16 or 32 bit precision. Ati cards do 24 bit precision, which is the dx 9 standard.24 bit is the dx 9 standard because it's "good enough." It's much faster than 32 bit, and much better looking then 16 bit. So 16 bit will wear out sooner. Of course, someday 24 bit won't be enough, either, but there's no way of knowing when that'll be.
Anonymous User - Friday, September 12, 2003 - link
Valve says no benchmarks on Athlon 64! :-/Booo!
Quote:
http://www.tomshardware.com/business/20030911/inde...
"Valve was able to heavily increase the performance of the NVIDIA cards with the optimized path but Valve warns that such optimizations won't be possible in future titles, because future shaders will be more complex and will thus need full 32-bit precision."
The new ATI cards only have 24bit shaders!
So would that make ALL current ATI cards without any way to run future Valve titles?
Perhaps I do not understand the technology fully, can someone elaborate on this?
Anonymous User - Friday, September 12, 2003 - link
I agree with #23 in terms of money making power the ATI/Valve combo is astounding. ATI's design is superior as we can see but the point is that ATI is going to get truckloads of money and recognition for this. Its a good day to have stock in ATI, lets all thank them for buying ArtX!Anonymous User - Friday, September 12, 2003 - link
I emailed gabe about my 9600 pro, but he didnt have to do all this just for me :DI love it.