AltiVec implementation in the PPC G5
Does anyone have any info. on the AltiVec/Velocity Engine implementation in the PPC G5? I have heard about new bus topologies, RapidIO, deeper pipelines, IU and FPU enhancements, higher clock speeds and new manufacturing processes, but nothing about AltiVec. It had better implement AltiVec as good as if not better than the current G4s.
Comments
<strong> The G5's memory will stay at a max of 1.5Gb and 4 hard drives.</strong><hr></blockquote>
How can a 64 bit chip be stuck at 1.5Gig 'o RAM?
<img src="confused.gif" border="0">
As for AltiVec in the G5....don't believe anything you hear about the G5 and AltiVec. Concentrate on the G4...because thats the only CPU Motorola will be selling to Apple in the near future. The G4 will be a monster CPU as soon as Apple implements a better memory subsystem (hopefully RDRAM with L3 DDR SRAM; high bandwidth + low latency = good) and a faster front side bus.
From a business perspective, its unlikely that Apple will accept a CPU from Motorola that doesn't implement an AltiVec-compatabile SIMD unit...given the strong emphasis toward AltiVec optimized code in Apple's homebrewed software (FCP3, OSX, iMovie, iTunes, etc) and ISVs' software (which Apple pushed Adobe to use).
[ 02-23-2002: Message edited by: mslee ]</p>
Trivially simple to do. Simply don't design the chipset to allow for more.
<strong>
Trivially simple to do. Simply don't design the chipset to allow for more.</strong><hr></blockquote>
Is this a marketing decision, as in "let's hamper this chip so they'll have to come back and buy another CPU in 6 months", or is this a technical consideration?
[ 02-24-2002: Message edited by: Matsu ]</p>
<strong>Be forwarned, I know nothing, but I've heard it mentioned that the number of RAM slots on the board has to do with lengths of the paths on the printed circuit board -- that's the reason apple dropped from 4 RAM slots to 3. With a largest available Dimm of 512MB (untill recently) that set the max RAM at 1.5GB. OSX recognizes up to 4GB right now. I bet if you could get compatible 1GB dimms, you'd up the max ram capacity to 3GB (even on current machines)
[ 02-24-2002: Message edited by: Matsu ]</strong><hr></blockquote>
Yes, timing issues and electrical noise limit the length of RAM traces. With each succeeding generation of memory that runs faster these limitations are usually increased forcing the memory to be placed closer and closer to the memory controller. This stability issue forces most motherboard manufacturers to settle for 3 DIMM slots if they want their time to market to be aggressive.
Edit: benchmarks detailing the asswhupping of a dualP4 Xeon vs 1.2 Ghz Athlons.
There's many more benchmarks on both sites, take a gander at them if you have the time.
And I'd like to take this opportunity to remind you that that is a 1.2Ghz Athlon. The new athlon core scales to higher much frequencies, and I believe 1.2 GHZ is the absolute low-end you can buy.
I'd also like to point out that the dual athlon setup used here would cost you about a grand, and the Dual Xeon/RDRAM combo will set you back at LEAST 3 times that.
The word 'suck' is somewhat relative, but I'd like to know where you draw the line between sucking and not. Price/Performance? Performace/Power dissipation? Or just performance? Not sure what your criteria is.
I have to admit, I kind of have my eye on a Tyan Dual 1.4 Ghz box...
[ 02-27-2002: Message edited by: stimuli ]</p>
take a deep breath...and realize that those Xeons were running a crippled memory subsystem...realize that those Xeons weren't northwoods....realize that dual CPU comparisons are x^2 more complicated than single CPU comparos.
Go find some benchmarks with a 2.2 northwood vs. an AMD XP2000+
A realbench mark too.
[ 02-24-2002: Message edited by: mslee ]</p>
<a href="http://www.vr-zone.com/reviews/Intel/P4-Northwood/page7.htm"; target="_blank">http://www.vr-zone.com/reviews/Intel/P4-Northwood/page7.htm</a>;
While a 2.6 Ghz Northwood does slightly best a 1.67 Ghz Palomino, for a chip running almost a Gigahertz faster, and that costs $228 more*, you'd kind of hope it would.
*Edit: Actually, the 2.2 Ghz P4 costs $228 more, they don't have 2.6Ghz P4s there.
Pricegrabber:
$467 2.2 Ghz Northwood
$239 Palomino XP2000 (1.67Ghz)
The Northwood is a substantial improvement over the original P4 (die shrink + double L2 cache?), and intel doesn't suck nearly as much as I originally thought, though i'd still argue the Athlon is a superior chip. The only reason the P4 N has any performance lead is the new .13 micron process, and when AMD hits .13, it will start all over again.
When you consider heat (not so bad on the Northwood, actually), power, size, cost, L2 cache size, and performance, It's kind of remarkable how little intel can do with so much.
But yeah, point taken nonetheless.
[ 02-25-2002: Message edited by: stimuli ]</p>
But anyway, i fully expect the G5 to have altivec. probably using ddr ram, instead of Rambus(which imo rambus is a better technology than ddr). Limited to 3 slots of ram(ddr), 4(or god forbid 2) if they go with rambus.
But hey, lets all remember that this is apple and motorola, so expect nothing more than a speed bump up to 1.2GHz G4 in the next 12 months.
<strong>What I would like to know would be how many frames a second a G5 with a GF4 Ti would get at the resolution of 1600x1200in Quake 3. If it gets 150fps, then I'll be very happy, as then Apple could proudly name the pro mac, a real PowerMac. <img src="graemlins/smokin.gif" border="0" alt="[Chilling]" /> </strong><hr></blockquote>
No, then they could say they have a Gamer's Mac. As long as the PowerMac is fast for Photoshop, other graphics programs, video, and runs all your office software it can be called a PowerMac.
You do realize, that although it runs at say 400mhz, it is 16 bit? And that my laptop has (ie) 64bit ram?
Besides low latency (getting the data to the processor at first), it has no real performance advantage?
Take another gander at the benchmark graphs comparing the RDRAM-P4 and DDR-Athlon.