More on the PowerPC 970 386
functor writes "Ars Technica's Jon Stokes has a treatise up covering the microarchitecture of the high-performance 64-bit PowerPC 970 microprocessor, due to be released by the end of the year, that goes over in detail how this chip is put together, and how we can expect it to perform. This is the follow-up to Stokes' article detailing the PPC 970's design philosophy. 'It appears to hold quite a bit of promise in bolstering Apple's currently almost obsolescent product line, and it appears to have been designed explictly to fulfil Apple's requirements. To say the least, the second half of this year looks to be pretty interesting as Apple's product line promises to become competitive performance-wise with IA-32 and x86-64-based PCs again.''
Re:No matter how many times I read it... (Score:4, Informative)
Re:No matter how many times I read it... (Score:3, Informative)
Some applications, e.g. large databases and applications that deal with very large integers, will benefit from being rebuilt with 64-bit addressing and 64-bit instructions, but for the vast majority of (desktop) applications that run on OS X, all 64-bit binaries will do is to increase the utilization of CPU instruction cache (and often data cache), and hence reduce performance as the cache miss rates go up.
So, in the end, don't worry; your OS X applications will run fine (for the most part) on a PowerPC 970-equipped Macintosh.
Re:Power, PC's, and PowerPC's (Score:3, Informative)
Re:No matter how many times I read it... (Score:3, Informative)
It's not that weird right now - their cooperation on PowerPC started almost 20 years ago. But it was weird ineed back then. I heard that on their first date, pardon, meeting, engineers of both companies wore the other company's dress code. The IBM guys came in jeans and t-shirts, the Apple guys came in suits and ties. How desperate both sides were to show each other that they have no hard feelings about past!
Re:Inaccuracy, Part 1 (Score:5, Informative)
They can't make the FSB DDR or QDR without appropriate support from the processor, and that's exactly what they haven't been getting from Moto.
Re:competitive, sure... (Score:5, Informative)
As Nethack would say, "Ugh! This meat is tainted!"
The 970 is fundamentally a 64-bit processor, and its performance must be evaluated in that context. The fact that the 970 will pull off amazing speed in the 32-bit arena only shows how well-designed this processor is.
Keep in mind, the Hammer is only shipping at 1.4, 1.6, and 1.8 GHz - the same speeds the 970 is targeted at. And the 970 has the advantage of an ISA that was designed from the beginning to do 32 and 64 bit addressing, versus one that's a 64-bit extension of a 32-bit extension of a 16-bit micro with full compatibility to an 8-bit redesign of a 4-bit processor.
AMD is the odd man out (Score:5, Informative)
Presumably the P4 can reach higher clock speeds than the Athlon because there is less work to do at each pipeline stage. On the other hand a longer pipeline increases the probability of a stall, so the work done per clock cycle goes down.
I'd speculate that the PowerPC ought, therefore, to be able to achieve clock rates approaching but not equalling the P4, since they are both comparatively "over-pipelined". At the same time, the PowerPC ought to deliver slightly more throughput per clock cycle because the pipeline is slightly shorter.
Meanwhile, the Athlon will be running at a significantly lower clock rate, but delivering comparable throughput.
Re:Inaccuracy, Part 1 (Score:5, Informative)
Re:Dual FPUs! (Score:2, Informative)
That is very bandwidth intensive work, moving alot of floating point numbers from memory, and this is where the 970 will be superior to the G4e. But this is also the strong point of the Intel P4 running at super high frequencies. The AMD Athlon 64 will clock for clock be competitive with the P4 running genreal code, but doing SIMD operations they can all do 4 at a time. Then the higher clocked chip always wins. The Altivec unit of the 970 will have to be alot better than the SSE2 from Intel to beat it.
Re:Hehe (Score:3, Informative)
"Why did Intel rename the 586 to Pentium?"
"Because they added 100 to 486 and got 585.999999878787775555"
Re:64-bit Adobe apps (Score:3, Informative)
Re:Kitchen Sink (Score:5, Informative)
A lot of these tricks (high decode bandwidth, multiple instruction queues [really buffers meant for reordering the instruction stream], branch prediction, etc.) are meant to reduce hazards such as pipeline bubbles as far as possible, and the PPC 970 does these hazard-reducing operations rather well, too.
And, yes, we're now in the post-RISC world where instruction complexity (particularly in the realm of SIMD and streaming/explicit cache manipulation instructions) is growing because simple instructions clearly aren't enough to allow for great throughput increments.
(Read some of Stokes' older articles in the Ars Technopaedia; I'm sure you'll find them interesting.)
Re:AMD is the odd man out (Score:5, Informative)
Combine this with the more intelligent branch prediction, out-of-order execution etc in the 970, and you're probably looking at a chip which is slightly less efficient clock-for-clock than the G4+, but more efficient than the Pentium 4.
Integer performance wise, it looks like the 970 will be about equal to a Pentium 4 of 25-50% higher clockspeed; FPU-wise, and of course Altivec-wise, it looks like a monster. So; it probably won't outperform the current Pentium 4s at a lot of tasks, but will kick it about on other more specialised tasks, which is a big step over the G4+. We're not looking at a Pentium-crusher, but we are looking at something that will be vaguely competitive.
Just gotta see how well it scales, after that, and whether 64-bit will mean anything for average tasks... and when it actually happens, of course.
Re:waiting for this to arrive.... (Score:4, Informative)
I'm intrigued. What do you do that makes a 1.25GHz G4 feel slow? I'm still using a 1.33GHz Athlon and it feels quite fast. I keeps thinking about upgrading the CPU, but really can't see the point. I rarely use more than 20% of it as it is...
Re:OS X not "more productive" for me (Score:2, Informative)
I'm not posting this to beat up on the parent but it's something that tends to come up often.
Re:Obsolete my a$$ (Score:2, Informative)
a: no longer in use
b: of a kind or style no longer current
therefore ALL computers are most certainly NOT obsolete as soon as they are bought, just as a perfectly functional computer that happens to be a couple of years old isn't. Obsolete - in computerese - generally means NO LONGER SUPPORTED.
Re:Dual FPUs! (Score:3, Informative)