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IBM PowerPC 970 Architecture
riclewis writes "Hannibal from Ars Technica offers an explanation of some of the internals of the new IBM chip. It's certainly more powerful than anything on the desktop now, but by the time it's released a year from now, it looks to be middle-of-the-pack (which could still be a step up for Apple...) This excitement over the early release of hardware specs kinda reminds me of all the hype surrounding the Sony's Emotion Engine when it was introduced a couple years ago. In fact, some are suggesting the PPC 970 chip might be closely related to the PS3's 'Cell' processor..."
Depends....where do you want to go today?
Cheers,
Ian
"In fact, some are suggesting the PPC 970 chip might be closely related to the PS3's 'Cell' processor..."
Even though it's really doubtful, it'd be extremely cool to see a PS3 emulator on the mac if the processors are that closely related.
I remember running Mac OS 6.0.5 on my Atari ST. Because it had the same processor, it didn't need much to make it run.
Oh well, I can at least dream, can't I?
This could help push Apple back to a respectable market share over a couple of years. A *nix box with a decent processor and lots of commercial software? Of course, Apple has proved to be just as fierce in protecting their proprietary code as Microsoft, so I wouldn't expect the price to drop significantly for every million sold. But still, alternatives (especially of this caliber) are good.
Unlike the P4, the 970 does one more trick after it has cracked the PPC instructions down into iops. The 970 divides up the iop stream into "groups" of five iops a piece. So first it cracks the PPC instructions down into iops, then it collects the iops back together into groups. The iops are placed the group's five slots in program order with the stipulation that all branch instructions must go in slot 4 (the last slot). Furthermore, slot 4 can hold only branch instructions and nothing else. It is these groups of five iops that are dispatched in-order to the issue queues. (I haven't yet seen a functional diagram of the 970's core, so I'm not sure how many issue queues there are.)
computing in chunks... sounds a lot like a Cray. Together with the 900MHz-effective (jesus... that's a lot) FSB, Apple really will be selling supercomputers in the next few years.
But what do I know. I'm just looking for anonymous gay sex.
when the p4 debuted it was sort of average too... the p4's power has come from it's ability to scale to higher mHz ratings pretty quickly. what kind of life are they going to get out of this chip? if it's going to top off at 2gHz then it doesn't really seem worth it, but if they can chip can get up to 3 gHz or so within a year of its release...
The PowerPC 970 triples the length of the PowerPC pipeline
This will give it the same issues the P4 has. Namely a large penalty for branch mispredicts, etc. Instructions per clock will decrease.
OTOH, they should be able to crank the speed!
The law is a weapon of the government, not a protection for the likes of you. Surely you understand that.
You are right, most of us can't wait, at least those of use with really old Macs (about to retire my Beige G3 in fact). I just ordered one of the Dual 1.25 GHZ machines and that should be more than enough power for me for some time. I'll move up to a 64 bit Mac in 3-5 years when they've worked out the kinks and about the time most people quit making 32 bit apps.
I did at least learn my lesson with the Beige G3 when it comes to jumping onto the latest thing just as it first comes out. While my old Beige G3 Rev A box has been a fairly solid machine for the past 5 years, it does have some serious shortcomings (possible voltage regulator blow out if upgraded to a G4, 66 MHZ bus (ick) and Rev A rom means no IDE slave support!).
I feel fairly confident this possibly last of the line G4 should be fairly solid other than the chips not fully utilizing DDR (at least DMA operations will take advantage of it) and the silly idea of making the second IDE channel only ATA66.
Once the issues of moving to a 64 bit chip and the new Hypertransport bus and such are worked out and my machine starts to look as slow as my Beige G3 is now compared to the latest machines, then I will start itching to move up.
--Won't that be grand? Computers and the programs will start thinking and the people will stop. - Dr. Walter Gibbs
"Hannibal" also has an incredible knack for making the workings of microprocessors understandable to those with no hardware engineering backgrounds.
// I will show you fear in a handful of jellybeans.
> Instructions per clock will decrease.
.09 process shows me that this 970 chip has legs. Another thing... IBM has *always* been conservative about what not-quite-ready chips will do as far as clock, and benchmarks. I expect "Real World" [no relation to Peter Gabriel] performance to be quite good. [although I expect Peter Gabriel's performances to be fantastic =)]
Actually, IPC is *increased* from the current G4. It will now fetch 8 instructions per clock, and retire 5 per clock.
The current G4 IIRC fetches either 3 or 4 per clock. I have no idea how many it can retire at once.
This coupled with a quick move to a
Blocklevel: Practical Information Architecture
Does it?
The eetimes story linked at the top says it's an 8-stage pipe. That doesn't mean any more or less than the extreme tech statement that the new pipe is triple the length (which would be 21, the current pipe is 7) since we haven't seen any actual reference docs from IBM.
Can anybody who was at the Microprocessor Forum give us more info?
Don Negro
Perl 6 will give you the big knob. -- Larry Wall
I have no idea who you are, Mononoke, but I'd wager $1000 that Hannibal Stokes knows more about chip architecture than you do. The PPC 970 will have a hard fight (both in marketing and benchmarks) against the 4+GHz x86 chips also due a year from now.
p.s. How the heck did that get rated as Insightful? I'm as rabid a Mac addict as any of you, but it's just plain wrong to mod someone up for spouting false evangelism.
Well, I'll try.
rendering apps like Lightwave, Maya, etc will benefit from this for several reasons:
The 64bit architecture:
Lightwave [if rewritten to be 64bit] will be able to use bigger numbers, and use more memory. Bigger numbers means that calculations that would involve making a 64bit word out of 2 32bit words [as it currently stands] needn't be done. Being able to address more memory is *always* a good thing.
Really good Floating Point Performance:
3D rendering apps love FP. bigger/faster/more Fp units are a good thing.
Memory Bandwidth:
The 900MHz bus will allow a *huge* amount of memory to be shuttled back and forth from the processor *very* quickly. This means your huge scenes will be rendered faster.
Altivec/Vector Processing unit:
Because the VPU doesn't do double precision FP, it doesn't help in the final rendering [much]. It *will* help in things like realtime previews, where the math is simplified. Imagine *big* previews of scenes in realtime.
Multiprocessing:
This chip is [as implied] MERSI compliant. This means that it is a perfect candidate for multiprocessing, like the current G4.... but the 970 can go many more "ways" than the G4 [the G4 was in an "optimal" multiprocessing stage with 2 procs]. The 970 can go up to 16, IIRC.
This seems like it'll be a winner.
.
Blocklevel: Practical Information Architecture
Contrary to some of the opinions presented recently it is just fine for Apple to use the 970 and be behind the curve with respect to typical performance. Sure there are specialized apps that can leverage a RISC architecture to outperform x86 or leverage Altivec to outperform SSE, but that is a small minority. Typical performance lags behind PC a little but we are in a situation where PCs and Macs have more performance than most people actually use. Most folks out there in the real world will get along very nicely with a 1GHz PC or a 800MHz Mac. Very few people need 2.xGHz machines, and only a few more have enough disposable income to buy those machines for Quake FPS pissing contests :).
The real Apple problem is that the gap between typical PC and typical Mac performance is starting to grow beyond the range that has historically shown to be viable. Not a problem today, standard dual CPUs counter this to a degree, but it's likely to be a problem in a year or two. While the 970 may only perform like a 3GHz P4 (SPEC), lag whatever Intel/AMD has in a year or two, it will be close enough. Apple will be back to a point where the typical performance gap is small enough. Apple has sold tens of millions of Macs that lagged PC counterparts in performance. They know that their customers are more interested in ease of use. Performance wise close-enough is all they need.
PPC chips can only work on one swing of the computing "cycle", not on the up and down like an Athlon can for example
It's called positive and negative edge triggering. It's not a new technology either. I was dealing with it in the 80's at the discrete logic level.
AGP 2x uses this and 4x uses positive, negative, high and low triggering. Certain UDMA modes make use of this clocking technique also.
Your argument doesn't hold water.
His arguement DOES hold water. PPC CPU's DO outperform Intel x86 CPU's by a good margin when compared clock for clock (showing the MHz Myth for what it is). Especially the G4 and boy when AltiVec can and is exploited... Wow. There IS more to CPU design than smaller die and deeper piplining for higher MHz.
As far as I can tell, Apple seem to be in a position where they have to make the best of what they can get, due to Motorolla dropping the ball pretty baddly.
I hope IBM comes to their rescue. How ironic.
War crimes, torture, lies, illegal spying... Would someone give Bush a blowjob, already, so he can be impeached?