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Carmack on NV30 vs R300
Nexxpert writes "John Carmack has posted his thoughts on the NV30 vs R300 (featured via www.bluesnews.com. Highlights some of the shortcomings of Nvidia's next step as well as pointing out what they've done right. Interesting read." In particular the arb2 vs nv30 path differences mean that it's not as simple as saying "ATI roX0rs nVidia" or vice versa.(update: sorry bout the misspelling, don't know how I missed that)
it's not as easy as it seems. Carmak makes some well reasoned and vaild points. I can't say I disagree with him about why DX's evolution is somewhat better(esentailly central control of the standard vs vendor squabling leading to dead branches). But he mentioned something about next gen cards having less bandwidth. Does that make sense to anyone?
Notice that Carmack has no R300 path. Why is that? I can think of two possible explanations instantly.
One is that ATI has optimized for the standard ARB2 path, and a specific R300 path wouldn't make much difference. In that case, my response would be, kudos ATI for promoting the standard, but speak positively of the performance of NV30.
The other possibility I can think of is that the lack of an R300 path is punishment for ATI leaking the Doom III alpha version. In that case I wonder how much the Radeon 9700 Pro would gain from an R300 specific path.
It certainly isn't a lack of time to develop the ATI path; there is an R200 path for older Radeon cards, and the Radeon 9700 has been available to developers for quite a bit longer than the GeforceFX has.
"The current NV30 cards do have some other disadvantages: They take up two
slots, and when the cooling fan fires up they are VERY LOUD. I'm not usually
one to care about fan noise, but the NV30 does annoy me.
Noise is becoming a big problem. I now putting zalman stuff in all my computers. My guide is a zalman heatsink, a zalman powersupply, athlon 1.2, seagate 40 Gig HD, ATi radeon 9000(whitout fan) and a good motherboard without fan on the chipset.
thank you
louis
I was holding out on nVidia's new card, but now I've given up on that idea. With more and more people using PCs as multimedia devices (watch DVDs, listen to music, etc), a fan that puts out almost 60Db of noise is unacceptable.
I really wanted to go away from ATI this time around, but it appears I'll have to wait a little longer. I'm sure nVidia will [eventually] release a fanless, 1-slot version. I just wonder if it will be too little too late.
3 rooms and 4 mobs does not a stress test make
okay I agree with the premise that older cards will do just fine but the Doom3 alpha wasn't pushing the limits like I expect the ifnal release to do.
A couple of dynamic lights and some bump mapping.
You can still get q3 to reach the limits of the Ti4600 128Mb. Heck, even the original Unreal still poses a test with eveything turned up!
There are places where the networks are not touching,and there are places where they are-Boeing's Lori Gunter
To my knowledge, all you'd have to do in order to use a longer shader is to break it down into separate passes. What the nVIDIA card does well, is extremely long pixel-shaders in once pass (1024 vs. 255 instructions, I think?), and also insanely long vertex shaders in one pass (1024x64 loops vs. 255x1 loop).
If you do more passes, as I understand it you have to upload all the scene geometry again, which is stressful on bus bandwidth and wasteful of processing resources.
Of course, it's entirely possible I'm misinterpreting everything, and I apologise in advance if that's the case.
~Rolphus
Yes ATI did good. I'm still worried about the shader limits though. There are some neat algorithms that use the shaders quite heavely.
BTW I'm waiting for someone to add geometry processors to cards. Download the model, and real-time morph, and other permutations. It could even help with primatives manipulation.
He's right, ATI has really only gotten its act together with drivers in the past3-6 months. Up till then it was one buggy driver after another. For most people the nvidia drivers just worked while it seemed that with every ATI driver release you ended up needing patches for every game to work right. That said at this point it does seem like ATI finally got things right with the 9700. Up till now I honestly wouldn't even consider an ATI card, but compared to the initial FX I don't see why you choose it over the 9700. The more I read about it, it seems like Cost, noise, and loss of a pci slot will be keeping me away from the FX. Right now I have a 4200 and by the summer I'll be ready for a new card. If Nvidia doesn't get its FX in line by then there's no doubt I'll jump to ATI.
If you wanna get rich, you know that payback is a bitch