x86-64 a viable choice for Xbox2?

[zurich]

I was thinking about this last night... would x86-64 (Athlon 64) be a good choice for Xbox2? The extra registers would allow for increased performance due to compiler efficiency, while maintaining backwards compatibility with x86 for original Xbox games.

The one downfall I'd see would be the integrated memory controller. I don't think MS would be able to take an off-the-shelf PC Athlon 64 and create a compelling gaming solution based around its, say, dual channel PC2700 memory system (atleast for 2005).

However, if MS licensed AMDs ISA and created a variant of it (with say, an NVIDIA controller), would this be a better choice than say, an HT Pentium 4 4ghz (speculating)?

That is, would devopers prefer the registry flexibility with the familiarness of an x86 backend to an off-the-shelf Intel solution?

!=

 

[Qroach]

hmmm, interesting thought. We've already heard rumors of AMD possibly being in the next Xbox, and this would be a good way to move things forwards...

 

[bryanb]

I was thinking about this last night... would x86-64 (Athlon 64) be a good choice for Xbox2? The extra registers would allow for increased performance due to compiler efficiency, while maintaining backwards compatibility with x86 for original Xbox games.

!=

You have to factor in the business side. Does it make sense from AMD's perspective to be in the XBox?

AMD could have been in XBox 1. Intel came into the project late and musculed AMD out with some ridiculously low pricing on those Celeron's that you see in the current XBox. Intel is selling those Celerons at or below cost. The same will happen with XBox 2.

AMD won't be in the XBox 2 if it won't make them money. They don't have the extra FAB capacity to churn out XBox CPUs that won't make $$$s. Intel has the luxury of too much FAB capacity. Intel has the luxury of keeping outdated FAB capacity around that can make outdated Celerons.

I'd say its highly unlikely that AMD will be in XBox 2.

 

[Tagrineth]

bryanb: It isn't a Celeron, though... it's about halfway between a Celeron and a Coppermine. I forgot the numbers, but the cache isn't literally split in half - the associativity of the cache is still P3-level. Celerons have it cut in half.

 

[V3]

Why don't they go with something else ?

 

[bryanb]

Why don't they go with something else ?

I think VIA and their Cyrix descendent is the only other choice. And VIA isn't pushing performance on that line of chips. The VIA chip is a super low cost, low wattage chip that doesn't push the envelope at all.

Its a prestige thing too. With XBox 2, Microsoft has to be able to say that they have got the latest and greatest. Marketing an XBox featuring a VIA or x86 knock off won't fly at all.

It will be interesting to see if Intel is being hurt by maintaining an old manfacturing process to support the XBox, and that causes them to push up the margins on XBox 2 chip. That would further hurt Microsoft and their ability to push down costs on XBox.

 

[Magnum PI]

are we sure the xbox2 will be the x86 (or even x86-64) based ?

i don't know if xbox compatibility is envisaged.

if it is, i guess the xbox2 gpu would have to be similar enough and maybe another nvidia chip ?

 

[Qroach]

I'm pretty sure we won't see MS stray away from one of the few advantages they have. That being the X86 platform and developing on it. Who knows, perhaps they'll switch to somehting a little more PowerPC based. (although I seriously doubt it).

 

[zurich]

are we sure the xbox2 will be the x86 (or even x86-64) based ?

i don't know if xbox compatibility is envisaged.

if it is, i guess the xbox2 gpu would have to be similar enough and maybe another nvidia chip ?

MS has to match Sony bullet point for bullet point. In this case, it's backwards compatability.

 

[Qroach]

That's a good point. having backwards compatiabilty is probably going to be a big feature for both PS3 and Xbox2. I usually forget about that...

 

[KnightBreed]

I think VIA and their Cyrix descendent is the only other choice. And VIA isn't pushing performance on that line of chips. The VIA chip is a super low cost, low wattage chip that doesn't push the envelope at all.

Intel?

 

[megadrive0088]

I don't see how XBox2 is going to be able to compete with PS3 using an off-the-shelf Intel or AMD CPU. How could a Pentium4 or AMD Hammer
compete with CELL? The variant of CELL going into PS3 is ment to have 500 million transistors, using hundreds of Cell processors and thousands of sub-processors. (speculative, but that is what has been reported by different scources)

XBox2 is gonna get STOMPED, CPU-wise. unless MS finds someone producing an equally parallel/multi core CPU. The only way XBox was able to compete with PS2 is with a monster GPU from Nvidia. but things are probably going to be different next time, with Sony-IBM-Toshiba's massive parallelism. that's not even starting on the graphics chip going into PS3 (the graphics synth 3)

I mean, the way things sound now, XBox2 is probably just going to be a
3-4 Ghz Intel P4, an Nvidia NV40 or NV50 variant and some DDRII memory thrown together.

 

[BenSkywalker]

XBox2 is gonna get STOMPED, CPU-wise.

The XBox and GC both are significantly outclassed CPU wise now, lot of good that's doing the PS2

The only way XBox was able to compete with PS2 is with a monster GPU from Nvidia. but things are probably going to be different next time, with Sony-IBM-Toshiba's massive parallelism. that's not even starting on the graphics chip going into PS3 (the graphics synth 3)

I would expect that GS3 will be roughly equally outclassed by the NV5X as the GS2 is outclassed by the NV2A.

I mean, the way things sound now, XBox2 is probably just going to be a 3-4 Ghz Intel P4, an Nvidia NV40 or NV50 variant and some DDRII memory thrown together.

Which is much like the philosophy used in designing the XBox(although if it is an Intel solution I would expect a Pentium5 core). The one area that you pretty much can't argue with in terms of the XBox is that amount of power it has in relation to the others.

 

[Tagrineth]

XBox2 is gonna get STOMPED, CPU-wise.

The XBox and GC both are significantly outclassed CPU wise now, lot of good that's doing the PS2

IIRC a few developers said that the Gekko can pull just as much work as the EE's r5900i (model number right?) and VU0... and if you use GCN's pure hard(wired) TCL, the whole thing in the end becomes about comparable to the entire EE.

 

[zurich]

I don't see how XBox2 is going to be able to compete with PS3 using an off-the-shelf Intel or AMD CPU. How could a Pentium4 or AMD Hammer
compete with CELL? The variant of CELL going into PS3 is ment to have 500 million transistors, using hundreds of Cell processors and thousands of sub-processors. (speculative, but that is what has been reported by different scources)

XBox2 is gonna get STOMPED, CPU-wise. unless MS finds someone producing an equally parallel/multi core CPU. The only way XBox was able to compete with PS2 is with a monster GPU from Nvidia. but things are probably going to be different next time, with Sony-IBM-Toshiba's massive parallelism. that's not even starting on the graphics chip going into PS3 (the graphics synth 3)

I mean, the way things sound now, XBox2 is probably just going to be a
3-4 Ghz Intel P4, an Nvidia NV40 or NV50 variant and some DDRII memory thrown together.

You forget that the PS2 needed that leg up in CPU power because the EE handled all the transformation & lighting, while the GS was just a rasterizer. If Sony is beating its chest about the CPU power in the PS3, one can only assume that again, the T&L logic will be decoupled from the graphics chip.

That said, any x86 unit that MS chooses + NVwhatever will still more than likely match or exceed the PS3's final output, while also retaining NVIDIA's developer-friendly architecture. I don't think its logical to assume that if SCE goes with this CELL wackiness, that it'll be as nearly as happy to program for as an NVIDIA platform.

 

[zurich]

XBox2 is gonna get STOMPED, CPU-wise.

The XBox and GC both are significantly outclassed CPU wise now, lot of good that's doing the PS2

IIRC a few developers said that the Gekko can pull just as much work as the EE's r5900i (model number right?) and VU0... and if you use GCN's pure hard(wired) TCL, the whole thing in the end becomes about comparable to the entire EE.

But half the strength of the EE is its programmability, so that's not really fair

 

[archie4oz]

bryanb: It isn't a Celeron, though... it's about halfway between a Celeron and a Coppermine. I forgot the numbers, but the cache isn't literally split in half - the associativity of the cache is still P3-level. Celerons have it cut in half.

SL5S puts it in the mobile Celeron family... Doesn't really matter what you call it (Celeron and Pentium are just marketing names for specific product segments).

would x86-64 (Athlon 64) be a good choice for Xbox2? The extra registers would allow for increased performance due to compiler efficiency, while maintaining backwards compatibility with x86 for original Xbox games.

The extra registers are only usable in 64-bit mode and I doubt you're going to double your code's memory footprint just to use 8 extra registers...

The one downfall I'd see would be the integrated memory controller. I don't think MS would be able to take an off-the-shelf PC Athlon 64 and create a compelling gaming solution based around its, say, dual channel PC2700 memory system (atleast for 2005).

Actually that could be a good thing. Better CPU/memory performance would be a boon. A lot would depend on the system architecture as a whole though. If you're going to build the same type of system architecture as the current Xbox, then it might not be so hot. If you segment it in a similar fashion like the Dreamcast then it might be advantageous.

AMD could have been in XBox 1. Intel came into the project late and musculed AMD out with some ridiculously low pricing on those Celeron's that you see in the current XBox. Intel is selling those Celerons at or below cost. The same will happen with XBox 2.

Actually it wasn't Intel coming in late, they were a candidate from the get go, even though AMD participated in the early system development. The Athlon's boom in success caused AMD to renegotiate their offer. They still offered a cheaper price on Athlons, but also wanted additional money up front. Intel made a better offer ( a 733MHz part vs. a 600MHz part for the same price, using depreciated factories, devleping the motherboard, providing debugging tools) in the end. AMD needed higher margin sales at that time, that 'Death Star' fab (Fab 30) in Dresden was still spinning up, and Intel (even though they hate selling cheap, low-margin parts) had the capacity to spare...

I would expect that GS3 will be roughly equally outclassed by the NV5X as the GS2 is outclassed by the NV2A.

I'd like to see how the NV2A outclasses the GS2 since there isn't a GS2 out...

IIRC a few developers said that the Gekko can pull just as much work as the EE's r5900i (model number right?) and VU0...

In terms of scalar performance it beats the EEcore quite handily. However it largely depends on the work you're doing. The one gotcha with Gekko is you can't run vector ops in parallel with the scalar core.

If Sony is beating its chest about the CPU power in the PS3, one can only assume that again, the T&L logic will be decoupled from the graphics chip.

Is there some law of physics that I don't know about that's going to make this a forgon conclusion (and is such necessarily bad)?

I don't think its logical to assume that if SCE goes with this CELL wackiness, that it'll be as nearly as happy to program for as an NVIDIA platform.

Hmmm... The NV2A is grossly parrallel, must to a total bitch to program for...

 

[PC-Engine]

In terms of scalar performance it beats the EEcore quite handily. However it largely depends on the work you're doing. The one gotcha with Gekko is you can't run vector ops in parallel with the scalar core.

And that's where the TnL unit comes in...?

 

[archie4oz]

No... I wasn't even factoring in VU1...

 

[Vince]

I would expect that GS3 will be roughly equally outclassed by the NV5X as the GS2 is outclassed by the NV2A.

<double checks name> Ben wrote this turd?

Besides the glaring nomenclature errors - You do realise that historically, with equal lithography processes - SCE is outpacing nVidia and Intel by a factor of over 4. Thus, if you take away the temporal advantage that MS had designing the XBox, the picture doesn't look so rosey.

The one area that you pretty much can't argue with in terms of the XBox is that amount of power it has in relation to the others.

Which is due to the extra R&D time between when PS2's design was finished as the XBox's was - according to MS, their won't be such a period this time around. While I know nVidia's part will be a beast, I wouldn't count SCE and their R&D buddies ouyt just yet.

The GS has 7M tranistors dedicated to rasterization only - what do you think they could have done if the lithography of the time (0.25um) wasn't constraining them?