xbox 360 specs (unofficial, but believable)

Re: 40GB

Wont this use VC-1 for encoding? it would seem it has the power?

 

Getting back to the 9bn dot products per cycle figure, does this reveal any "special sauce" on the vmx units, or is that what you'd expect to get out of 3 standard vmx units at 3.2Ghz (theoretically, of course)?

If a dot product is 4 multiplies and 3 additions, is that 7 floating point ops? So taking nAo's figure of 76.8Gflops, 76.8/7 = ~11bn dot products? Or if you round up to 8 flops (which you probably would do..can't do much with that extra spare flop per cycle per core..at least not another dot product), 76.8/8 = ~9bn? Is that were it comes from, or am I totally off track?

 

Great point.

 

you are right
cell 320Gflops / 8 = 40

 

My calculations assumed 8 ops per clock, I believe VMX units can do one fmadd per cycle.

 

If they launch with 8 DRAM chips with a 128 bit bus, then that sets a precedent for Sony and Nintendo to follow with that config, at least from a cost, heat and mobo traces POV it would seem feasable.

I'm pretty sure that 256 GB/s is 'effective' bandwidth and not 'true' bandwith as mentioned in the original 'leak'.

 

Mpeg4 support?

 

I'm pretty sure that 256 GB/s is 'effective' bandwidth and not 'true' bandwith as mentioned in the original 'leak'.[/quote]


yeah - the 256 GB/sec EDRAM bandwidth effective bandwidth was mentioned back in... no later than June 2004, and possibily earlier.

quote: Xenon Hardware Overview

http://forums.xbox-scene.com/index.php?showtopic=231928
http://www.beyond3d.com/forum/viewtopic.php?t=13470
http://www.google.com/groups?selm=51488ce2.0406222254.5a7434a9@posting.google.com&output=gplain

 

I'm still holding out hope that with a 256-bit bus, the main memory/system bandwidth will be double or roughly 2.5x greater than the ~22 GB/sec which is because of a 128-bit bus.

the old, old reported main memory bandwidth which was ~51 GB/sec, would be nice
(the one BEFORE the leaked Xenon Diagram and Hardware Overview)

a 128-bit bus is kinda disappointing since R300 in Radeon 9700 has had 256-bit since 2002. (as did other new G|VPUs of 2002)

 

most of the mid to low end boards still have only a 128-bit bus .

THe 9700 had one but was phased out before it hit 200$ and all the other boards from both ati and nvidia were 128 and lower


Though i would think it would have a 256bit bus now . In the future they could allways just use a 128bit buss with the faster ram .

 

but all *highend* ATI VPUs and Nvidia GPUs have 256-bit bus, or am I mistaken ?

 

R300 didn't have a 48 (256) GB/s extra bus dedicated to render targets.

 

But a high end board was 1 gpu with 256 megs of ram . Not a gpu , tri core cpu , 512 megs of ram , 10+ edram , sound chip , wifi and whatever else is in there like controler ports , usb and crap .

Huge diffrence .

256bit bus will never scale down in price slower than faster ram if it scales at all. It would also make the mainboard have more layers than needed which = higher costs .

But even i was thinking just southof 50 for main ram bandwidth

 

that's true, and I was going to add "but the EDRAM bandwidth offsets the relatively small main memory bandwidth" so it's all good >_<

 

It's a Low Cost Next gen, imho....Ps3 will be another world.

 

How do you fathom "low cost"?

 

In his mind where a 500$ system is low cost and a 500$ six months later will be a high cost system. ONly really because it says sony on it and not microsoft.

 

lowcost as in 2-4 times less powerfull

 

that sounds absolutely in-line with the 1 dp per cycle info : )

 

i immagine vliw means low budget tech low cost hardware compared to the other hardware producer , not low cost retail price