[Numpy-discussion] Numpy and the Pentium 4

Tim Churches tchur at optushome.com.au
Mon Apr 30 17:14:57 EDT 2001

Chris Barker wrote:
> Tim Churches wrote:
> >Our problem domain involves a mix of manipulating
> > very large integer arrays and then floating point calculations on
> > smaller arrays,  so FP speed is probably not of paramount importance,
> > but memory bandwidth and clock speed probably is (perhaps, maybe,
> > possibly).
> Have you checked out the PPC G4 option? Apple certainly like to
> advertise how fast it can be, which is ussually deceptive, but, in fact
> the one place iot does shine is large integer manipulations (in the
> Apple literature: "some photoshop applications"). I havn't done any
> speed comparisons, but we have found it to pretty fast when using the
> optimised BLAS from Absoft.
> Mac OS is pretty patthetic for this kind of application but PPC linux or
> OS-X should do the trick for you. IT might be worth a little
> investigating.

Yes, I had the same thought but it appears that the speed of the
CPU-to-main-RAM bus in the G4s leaves a lot to be desired, but the CPUs
do have a largish local cache which enables lots of speed on problems
with high locality. The other problem is that they don't come standard
with SCSI discs and our local Apple dealer seemed unsure what to do when
it came to SCSI. He had never heard of PPC Linux. Also, our local IT
support people just about tolerate us running Linux on Intel hardware
connected to "their" network, but the thought of throwing Apple OSs into
the mix would give them conniptions, I suspect.
> By the way, just how much does that 400 Mhz memory cost now?

I think the memory is only 100MHz but it is "quad-clocked" and "double
ported" or somesuch. Anyway, Dell Australia are quoting about AUD$2800
for "4 x 256MB PC800 ECC RAMBUS RIMM" - that's about US$1400. Seems
cheap to me, for somewhat specialised memory. Compaq were quoting nearly
three times as much for the same memory modules for their equivalent


Tim C
Sydney, Australia

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