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Yet Another G5 Roundup

Posted by pudge on from the you-thought-we-were-done dept.

Lawrence Person writes "This article on Low End Mac talks about why the PowerPC 970 is so fast, covering its superiority to Intel chips in Multiply Accumulate, double precision arithmetic, and Fast Fourier Transforms, among other operations. A short, clear article for those who don't have the time to wade through Parts 1 and 2 of Ars Technica's exceptionally detailed dissection of the 970/G5." Trollaxor writes "IBM has a neat two-page history of the PowerPC architecture, detailing its evolution from the first RS/6000 chipsets in 1990, through the POWER ISA, and into the processors that we know and use today. A very interesting read."

7 of 69 comments (clear)

  1. FFT is a good mesure by Baikala · · Score: 5, Informative

    Fast Fourier Transform is bread and butter for the scientific comunity. This is a good news for sys admins at research centers like me.
    Maybe I have a chance at getting one or two of these babies for the next year budget.

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  2. Re:Yea, but does it run Linux? by dhovis · · Score: 4, Informative

    I think the tech documents say that if the OS does not provide thermal management, the fans will run at full speed. So it will be interesting to see if the thermal management will be provided under Linux.

    Terrasoft (makers of Yellow Dog Linux) has said that they will support Linux on the G5, but it remains to be seen if they will be able to provide thermal management that won't void the warrenty. Terrasoft is an offical Apple Value Added Reseller, and they sell dual boot MacOS X/Linux systems that carry the full Apple warranty, so Apple may provide them with the info they need or else a binary driver that they can use.

    It may also be that Apple will make the thermal management code open source as part of Darwin. If that is the case, then it can probably be converted into a kernel module without violating either the GPL or APSL.

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  3. Re:Yea, but does it run Linux? by dhovis · · Score: 2, Informative

    You forget that Apple's thermal managment software is constantly monitoring things and if the temperature goes to high, the machine goes to sleep. In fact, the G4 Cube would sleep if you set something on top of it and blocked its ventilation. It didn't even have a fan.

    In fact, the 9 fans give you some amount of redundancy. Under normal operation, they turn at a low fraction (10%, IIRC) of their top speed to stay quiet (just 35dBA), so if one fails, the others can take up the slack with no problem. The fans should also last longer that way. They can probably put the "wind tunnel" macs to shame if they ever all get going at the same time.

    The failsafe on the software control is that if the software control is not present, the fans all go to full speed!

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  4. Re:Yea, but does it run Linux? by Anonymous Coward · · Score: 1, Informative

    locked ... G4 ... cutting

    Except maybe for that little tab with a hole and the icon of a lock on it that prevents case opening/removal if you put a padlock through it? :-)

  5. Re:Hold up... RISC vs CISC, folks... by fitten · · Score: 2, Informative

    First, RISC vs. CISC arguments died about a decade ago. What was RISC became Load/Store architectures because they have load and store operations for memory access and everything else is register based. Most so called "RISC" machines tended to have nearly as many (if not more) instructions than their "CISC" counterparts.

    I posted a while back (sometime in the past year) the number of instructions a G4 (including Altavec) has compared to the P4 (including SSE2) and the G4 had quite a few more opcodes than the P4. Feel free to look the post up or do the same research.

  6. Floating Point Units by yarbo · · Score: 2, Informative

    comparison table the Athlon XP has 3 full FPUs, the P4 has a full and a partial (I believe it only can do memory operations, not arithmatic).

  7. Re:But it's really only 32 bits by dhovis · · Score: 2, Informative

    The frontside bus is two 32-bit wide unidirectional busses. They run at 500MHz DDR (equivelant to 1GHz). That gives you 4GB/s in each direction, per processor. The memory is 200MHz DDR (400MHz effective) and 128 bits wide (2 64bit banks), yielding total bandwith of 6.4GB/s (3.2GB/s per bank).

    The width of the FSB is really irrelevant here. The most important thing is how fast you can get data into and out of the processor. The thing that makes it a "64 bit processor" is that it can handle 64-bit memory pointers.

    I mean, heck. The G4 had a 64-bit FSB running at 167MHz, but that doesn't give it much bandwidth and it doesn't make it a 64-bit processor.

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    The internet is the greatest source of biased information in the history of mankind.