Kinda OT; but... How does Xbox match PC perf??

dannyaa

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I wasn't sure where else to post this, but I thought you guys might know! So my question is this. The Xbox is equipped with a PentiumIII 733 & GeForce 3 - level card & 64 MB Ram. Yet, I saw the new Doom III trailer being played on the Xbox (amazing graphics!) and was wondering, how does this (what we PC-ers would consider an old, low-end system) manage to deliver the same graphical punch and smoothness as a top-of-the-line PC? Seeing THG's benchmarks from Doom III on the new GeForce FX 5900 & a P4 3.06 GHz, I would think a PC that was a PIII 733 w/64 MB ram & GeForce 3 would not run that game too terribly well, yet the Xbox seems to have no problem... how do they do it?

Dan
 

shadus

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Non-moving hardware platform.

They know exactly what hardware is available, and they don't have to worry about specific drivers and variations in drivers, versions of os, etc... If you want to see amazing differences look at some of the very early SNES games and then the later ones... the difference? The later ones had time for the programmers to optimize the code and move chunks into asm for faster access, etc. Same hardware, vastly different in appearance... another good example is the Final Fantasy series, look at the first and last ones on the PS1... What a massive difference.

Shadus
 

DOOM

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I'm not an expert on this topic, but I would suspect that the O/S on the XBox is also a lot more optimized toward gaming. On a standard Windows setup, there are a lot of services running and a good portion of the kernel that are needed for general purpose stuff: networking, security, file caching/indexing, running other programs in the background, etc.

-DOOM
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MOV DS,AX
MOV WORD PTR [0072],1234
CLI
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JimStapleton

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Wow, I wanted to answer this, but I don't think I could have said it better.

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stealth_blade

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and of course the last major difference, most games are a lot less demanding at 640x480, and thats what a TV is the equivalent of, also the g3 is rated to be able to play doom 3 at medium settings, and the processor doesnt have as large an impact on that kind of game

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edwpang

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yeah, 640x480 and 3D setting are probably the most important reason.

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Crashman

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You've heard why the X-Box executes custom code better than a PC equivalent with standard code, but what you also have to remember is that the X-Box is outputting at MUCH lower resolution. For instance, I encode video for standard TV's at 352x240 with minimal loss in quality. And even 740i HDTV is only 740x1024.

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phial

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the gpu and cpu exist on the same high bandwidth bus in the xbox. not like a computer, where the gpu sits on the AGP and the cpu sits on the FSB


and at over 5gb of bandwidth a second the fact that these sit on the same bus, accessing the same ram gives it a considerable boost compared to a PC with a p3 733 and TI500

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JimmyDean

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The doom3 running on the xbox was probably at around 640x480 or 512x640 or something. Plus it didnt have all the crazy 3d stuff. Granted it still looked good, but up close youd notice alot of difference

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imgod2u

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Firstly, the NV2A architecture in the X-Box resembles the Geforce 4 Titanium series more than it does the Geforce 3. Secondly, the X-Box supports resolutions up to 720p and as advanced a game as Doom3, I would expect them to use that resolution.
As for how they're able to run it. If you know the exact amount of RAM/cache/HD space, etc. you have in a platform and can be absolutely sure that no other process will take up any CPU time, you can time your data load with incredible accuracy. With such advantages it is indeed possible to optimize Doom3 for the platform and have it run well even at 720p resolutions.

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phial

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they wont be able to have the same shodowing and lighting ,because its only direcx8

but it will still look dam freakking good.

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