IBM roadmap: POWER5-lite processor to replace G5 in 2004?

[Eug]

Roadmap & PDF of presentation

So it looks like when the Power Macs are next updated (June?) they'll get G5 970FX chips (which are based off POWER4) running at 2.5 GHz or higher. Many had thought the following Power Macs after those would use G5 970FX chips too, but at up to 3 GHz.

However, it seems that the 3 GHz chips may in fact be based off POWER5, and should come out in 2004.

This is interesting since POWER5 supports SMT (and IBM claims its implementation is more powerful than Intel's Hyperthreading). POWER5 also supports DDR2, with an on-chip memory controller. If these features get implemented on a POWER5-lite, that's gonna make for some monstrously fast Power Macs.

ie:

Dual 3 GHz Power Mac with SMT (seen as quad processors)
1.5 GHz system bus, for each CPU
2 banks of dual channel DDR2-533

 

[Acanthus]

Well if it were power5 based it would cost around $250,000... lol

Unless its EXTREMELY scaled down, as the core on the power5 is massive (isnt it 8 core?)

 

[Eug]

Originally posted by: Acanthus
Well if it were power5 based it would cost around $250,000... lol

Unless its EXTREMELY scaled down, as the core on the power5 is massive (isnt it 8 core?)

Yes, it would be EXTREMELY scaled down, and would probably cost only a couple of hundred bux per chip.

The POWER4 chips are big (dual core), hot, and horrendously expensive too, but the PPC 970 and 970FX are based off that design, with much of the hard-core stuff removed, and with Altivec bolted on.

The POWER5 is even more complex than the POWER4, but it isn't 8 core. Each chip is dual core like the POWER4, but they put 4 chips together, so that's how you get your 8 cores. (They do the same thing with POWER4 actually.) Any desktop variant would again be hugely pared down and would only have a single core. Nonetheless, despite the scaling down I suspect the POWER5-lite will be very impressive by desktop/workstation standards, sort of like an Opteron on steroids. ie. with Hyperthreading and DDR2 support on an on-chip memory controller. (Neither the POWER4 nor the 970 have SMT or an on-chip memory controller.)

Take another look at that roadmap. You'll see:

GP - That's the POWER4.
GP-UL - Thats the PPC 970 in current Power Macs.

GR - That's the POWER5.
GR-UL - That's the PPC 97X, which should show up in future Power Macs.

IIRC, "UL" stands for "ultra-lite".

 

[jhu]

what differences are there between a theoretical single-core power4 and a ppc 970?

 

[Eug]

Originally posted by: jhu
what differences are there between a theoretical single-core power4 and a ppc 970?

I'm no CPU expert, but this article covers a bit of it:

IBM Trims Power4, Adds Altivec

Table 1 has a very basic spec comparison.

 

[KristopherKubicki]

No surprise here i think. Motorola is a sinking ship.

Kristopher

 

[Eug]

Originally posted by: KristopherKubicki
No surprise here i think. Motorola is a sinking ship.

Yeah, it's no surprise that Apple has ditched Motorola/Freescale for the high end, but they will keep them around for the lower end stuff.

However, the surprising part (to me) is that the POWER5 derived desktop parts may be coming this year. I had always assumed that the IBM PowerPC 970FX (which ships in current Xserves), would scale up to 3 GHz, for all new Power Macs in 2004. If one were to take this roadmap at face value, it would seem to suggest that Apple is going with a new chip design with every Power Mac revision.

Dual 2.0 GHz Power Mac - Shipping now with G5 PPC 970 (POWER4 derivative), on 0.13 um. This machine is what Anand runs.
Dual 2.5 GHz Power Mac - Likely will be announced in June, running G5 PPC 970FX (POWER4 derivative), on 0.09 um, with added power saving features
Dual 3.0 GHz Power Mac - May be announced by the end of the year, running a POWER5 derivative, on 0.09 um, with increased L2 cache, SMT and integrated memory controller

PPC 970 --> 970FX is not a big deal, since it's just a die shrink with some added power features.
However, 970FX --> POWER5-lite is a huge jump, assuming it keeps most of the upgrades that the POWER5 line got over POWER4.

I suppose "GR-UL" could just refer to 970FX (since the 970FX isn't actually referenced in the roadmap), but I don't understand why then it would have "GR" at all in the name, since that's POWER5. 970FX is a POWER4 derivative.

 

[anthrax]

Power 5 isn't very different from its its predecessor the power 4. The biggest changes is the relocation of the Memory controller and the L2 Cache and the implementation of SMT ....

Performance wise, per chip, its not much faster than the power 4. However, in SMP systems, it scales much better... Actually, chip to chip, I suspect the itanium 2 is faster...

 

[Eug]

Originally posted by: anthrax
Power 5 isn't very different from its its predecessor the power 4. The biggest changes is the relocation of the Memory controller and the L2 Cache and the implementation of SMT ....

Performance wise, per chip, its not much faster than the power 4. However, in SMP systems, it scales much better... Actually, chip to chip, I suspect the itanium 2 is faster...

POWER5 benches (More commentary in my sig link.)