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DOOM 3 & DX9

[Sep 17, 2003, 7:08 pm ET] - Share - Viewing Comments

With all the discussion lately about how Half-Life 2 will run on ATI hardware compared with NVIDIA accelerators, BonusWeb.cz shot off an email to id Software's John Carmack to ask how DOOM 3 and other games are likely to be impacted by the difference between the two graphics platforms running DirectX 9. Here's how he responded:

Unfortunately, it will probably be representative of most DX9 games. Doom has a custom back end that uses the lower precisions on the GF-FX, but when you run it with standard fragment programs just like ATI, it is a lot slower. The precision doesn't really matter to Doom, but that won't be a reasonable option in future games designed around DX9 level hardware as a minimum spec.

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94.

Re: the truth... is out there....

Sep 18, 2003, 13:58

m00t

I'll quote Mr. Carmack: "when you do an exact, apples-to-apples comparison using exactly the same API, the R300 looks twice as fast, but when you use the vendor-specific paths, the NV30 wins" quote source: http://www17.tomshardware.com/column/20030219/3dmark2003-01.html So when using the standard, R300 wins by double the speed. Vendor-specific path (What? the "optimisation" route? Graphics quality toned down, removal of special effects like fog?) then suddenly the NV30 wins. Sorry mate. I do believe in an equal playing field. The standard apples-to-apples comparison means a lot more than the apples-oranges comparison. (hope that italic worked) Reading the .plan this quote is from I gather the meaning to be this: There are a number of paths each card can take. Each path has its advantages (speed or quality) and it's disadvantages (poor speed or poor quality). What Mr. Carmack was refering to here is the ARB2 path. Both cards render this path with FULL FEATURES. Unfortunately due to the nVidia's card using full 32bit precision, it is much slower using this path. The nVidia cards also have a NV30 path that has all the same features, but is much faster (uses 16bit or 24bit precision? not sure which). The Bruhaha (sp?) over missing fog and the like in the .50 drivers (!beta!) is that they impliment one feature at a time fully as opposed to implimenting each feature partially. So each incremental release has more complete features than the last and no partial half-assed features. So NV30 (and arb2?) path running on .50 drivers will be missing features. When the final .50 drivers come out, these features will be implimented. I imagine nVidia might try to impliment support for using lower precisions on their ARB path, but I wouldn't count on it. So. if you can get your nVidia card to run on the NV30 path all the time, you should run faster with only marginal quality loss over the ARB2 path on the same card. Frankly, I'm still stuck on my TNT2 and will be for a while (You can't imagine how slow some games run on this card. BUT THEY DO RUN DAMMIT.!!!)

Subject

Comment [quote="m00t"Sep 18, 2003, 13:58]i[I'll quote Mr. Carmack: "when you do an exact, apples-to-apples comparison using exactly the same API, the R300 looks twice as fast, but when you use the vendor-specific paths, the NV30 wins" quote source: http://www17.tomshardware.com/column/20030219/3dmark2003-01.html So when using the standard, R300 wins by double the speed. Vendor-specific path (What? the "optimisation" route? Graphics quality toned down, removal of special effects like fog?) then suddenly the NV30 wins. Sorry mate. I do believe in an equal playing field. The standard apples-to-apples comparison means a lot more than the apples-oranges comparison. ]i (hope that italic worked) Reading the .plan this quote is from I gather the meaning to be this: There are a number of paths each card can take. Each path has its advantages (speed or quality) and it's disadvantages (poor speed or poor quality). What Mr. Carmack was refering to here is the ARB2 path. Both cards render this path with FULL FEATURES. Unfortunately due to the nVidia's card using full 32bit precision, it is much slower using this path. The nVidia cards also have a NV30 path that has all the same features, but is much faster (uses 16bit or 24bit precision? not sure which). The Bruhaha (sp?) over missing fog and the like in the .50 drivers (!beta!) is that they impliment one feature at a time fully as opposed to implimenting each feature partially. So each incremental release has more complete features than the last and no partial half-assed features. So NV30 (and arb2?) path running on .50 drivers will be missing features. When the final .50 drivers come out, these features will be implimented. I imagine nVidia might try to impliment support for using lower precisions on their ARB path, but I wouldn't count on it. So. if you can get your nVidia card to run on the NV30 path all the time, you should run faster with only marginal quality loss over the ARB2 path on the same card. Frankly, I'm still stuck on my TNT2 and will be for a while (You can't imagine how slow some games run on this card. BUT THEY DO RUN DAMMIT.!!!) [/quote]

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