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 workstation. Cheers, Tim C Sydney, Australia