OT: RE: [rescue] XBOX vs PS2

[Chris Kennedy]

Michael Dombrowski wrote:

[original attribution lost]

> > I'll stick with my PS2.  A nice R5600/200 or so Mhz MIPS processor,
> > lots of memory IO...and TWO vector processing engines.

Not R5600.  The CPU2 core is the TX5900, which executes an extended 
R5000 instruction set.  It's called a 128 bit processor, but 128
bit instructions lock step the two 64-bit integer pipes, which 
puts a damper on multiple issue; other weirdness includes on-board
scratch pad RAM (a page worth) that is a DMA _target_, introducing
the somewhat weird concept of doing DMA _to_ the processor.

It's true that there are two vector engines, although they differ in 
the number of floating point units and hardware visibility (one
can see the GPU2 chip, the other can't).  Both share a slightly
brain-damaged implementation of single-precision IEEE floating
point (as does the FPU on the 5900 core).

[snip]

> Come on, this is really, really, stupid. MS bashing just for the sake 
> of bashing is stupid. Who cares what's inside the console, it's the 
> games that matter. 

Well, actually, the poor bastards who have to cobble together bits
and pieces of code by hand care.  Game processors are weird
beasts; you can't do a process change, die shrink or anything else
that might affect timing once the thing ships because these guys
still do some hand-scheduling of instructions. I personally think
the x86 ISA is horrid and I'm certainly no fan of the TX5900 ISA
either, but at least with the TX5900 I _can_ schedule things so
I have no (or minimal) slips and stalls.  While the same can be
said for an x86 implementation it's harder to predict because the
ISA is more opaque with respect to underlying hardware state.

[snip]

> Most people I've talked to 
> think it's the better system, the PS2 does not have 4x controller 
> slots, the PS2 needs $40 memory cards, and the PS2 does not have 
> builtin networking. 

The fact that the memory cards for the PS2 go for $40 is definitive
proof that game consol hardware is given away.  Why SCE insisted
that we use RAMBUS for the TX5900 -- and why we had to support both
the sync and async specs -- remains a great puzzlement.

> The graphics look to be about the same to me on 
> both platforms but PS2 has had much more time to mature.

The graphics appear to be a wash, but given that people 
were still finding new ways to use PS1 hardware as recently
as three years ago I remain unconvinced that the PS2 set has
even scratched the surface on what to do with all of those
vector units.  The same may or may not be said for the "modified"
PIII that lurks in the Xbox.  Time will tell :-)

--
Chris Kennedy
chris at mainecoon.com
http://www.mainecoon.com
PGP fingerprint: 4E99 10B6 7253 B048 6685  6CBC 55E1 20A3 108D AB97