XBox2 specs (including graphics part) on Xbit

this is interesting

http://www.gamesindustry.biz/content_page.php?section_name=dev&aid=3364

Alleged Xbox 2 specification sheet debunked by experts

Rob Fahey 15:57 27/04/2004
"Leaked" diagram is a fake or, at best, an out of date internal document


A diagram purporting to be a leaked Microsoft document describing the specification of the Xbox 2 has surfaced on a Chinese bulletin board - but sources close to the console's development say that it is probably a fake.

The block diagram, which appeared on Chinese website GZeasy.com, shows a system architecture which had three 3.5Ghz CPU units, 256Mb of main memory, and a 500Mhz graphics chip with 10Mb of on-board memory.

The schematic also shows the system featuring two memory unit ports, with basic memory unit size being 64Mb, a 100Mbit LAN port and a hard drive - although it notes that it's not been decided whether to build in the drive as yet.

However, a number of sources who are familiar with Microsoft's console development say that the diagram is not an accurate reflection of the information they've received from the company about Xbox 2 - and could easily have been put together by someone with basic hardware knowledge from publicly available information about the forthcoming system.

"It's not impossible that it's a Microsoft document," one expert told us this afternoon. "But some of the figures seem very suspect, and the information included on the diagram looks to me like it reflects the available information about Xbox 2 rather than being a sensible set of information to put on a document for developers."

He voiced particular concerns over the fact that while the document notes "256+ Mb" of main RAM, it doesn't start what kind of RAM will be used - a vital technical point - and also noted that the CPU diagram doesn't mention that the CPUs used will be dual-core (effectively making Xbox 2 into a six processor unit), another important factor.

"There's a lot of detail here about stuff you could just guess or which we already know from public announcements, like some performance information about ATI's graphics chips. And then there's some really surprising missing detail, like the twin-core architecture and a few other really crucial things which Microsoft has already talked to developers about but are missing from this diagram. I'd have to guess it was a fake," he concluded.

Other developers familiar with the Xbox 2 architecture also voiced misgivings about the diagrams, with one pointing in particular at the information about the processor cache on the document as being inaccurate. "We've seen stuff about the cache on those CPUs from Microsoft, and this isn't it," he said. "If this isn't a fake, the only thing I can think of is that it's an old internal document that was a work-in-progress and never meant to be seen outside Microsoft."
 
JohnH, aaronspink -

Given the fact that 10MB of edram gives you a pretty giant tile size (even with high levels of AA), is it unreasonable to simply design for good performance under the assumption that the software will more or less take care of tiling for the hardware (since this is a system that will be targeted directly)?

I was thinking along the lines of basically splitting the screen into say 4x4 "mega-tiles". You could then specify to the EDRAM block a mega-tile which is guaranteed to be held on chip, perhaps uncompressed. Left-over space would be filled by fragments falling outside of the current mega-tile, and could be compressed/spilled to main memory as necessary.

Performance would suck if a developer didn't take the time to split (for example) giant screen aligned quads across the bigger tiles, but on such a fixed platform I think its a given that developers will avoid the things that really kill performance.

Regards,
Serge Monkewitz
 
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