PA-risc vs X86 performance

Hi there

So, if I play my cards right, I'll be able to get my hands on an HP PA-RISC workstation. Now, I know that a 800mhz PA-Risc is WAY faster than an 800mhz X86 chip, but is there any direct comparison with speeds, or are the curves different shapes?

Well, I hope you get what I'm trying to say, it's not very clear. I'm still not sure what I'm going to DO with the damn thing, it just seems cool to play with.

Thanks
Joe

Originally Posted by Joe of Loath Now, I know that a 800mhz PA-Risc is WAY faster than an 800mhz X86 chip, but is there any direct comparison with speeds, or are the curves different shapes?

I don't actually know how true that is these days, but I don't have numbers. Sure, the PA-RISC would have been way faster than a contemporaneous x86 chip clocked at the same level, but the efficiency of an x86 core in 'per-clock-cycle' terms have improved - probably by a factor of two, or so - since then and the cache sizes have grown considerably, too, so a 'modern' x86 chip clocked down to 800 MHz would be much closer, or perhaps even faster.

But then, the disk sub-system is probably some variety of SCSI, which may still be competitive (if small). And it may not have much memory, and any need to swap because you don't have enough memory really, really, does slow things down.

Bear in mind that PA-RISC was end-of-lifed at the end of 2008 in favor of Itanium, and therefore the chips were built using older tech. Therefore, as salasi said, while an 800 MHz PA-RISC would beat the pants off of an 800 MHz Pentium III, it's not likely to be particularly competitive against a modern Xeon or Opteron chip. People tend not to buy RISC chips for bleeding edge floating point performance nowadays (check the Top500 list; most of the world's top 500 supercomputers run some variety of x86, possibly in conjunction with specialized processors like the Cell or GPUs). The reason to go RISC these days IMO has more to do with integration and stability, as well as high-level transaction processing.

Thanks! This is one of the last generations (I only got a brief glimpse, but it seems to be an HP C3650/3750), with a maximum memory capacity of 8gb. It was being used for tape drive testing I believe, but of course as they're not being used much any more, it was pointless to use any further. I wish I could have got my hands on the older ones they had there, but they seem to have been removed.

Cool thing is, my dad used to work sith SCSI, so I have a loft full of SCSI drives and controllers. Unfortunately, the biggest drives are only about 5gb, but hell, it's not going to be a media center. I just want to fiddle really, it's challenge, just like linux on a 486 laptop with 8mb of RAM (I gave up for the time being and put windows 95 on it, even freedos was having trouble with it).

Thanks again, I'll probably be here again when I find a problem...

just like linux on a 486 laptop with 8mb of RAM

hint: linux needs about 10mb to boot.

Originally Posted by smeezekitty hint: linux needs about 10mb to boot.

I could get DeLi to bot into a perfectly functional busybox from live 'CD' (a partition on the SD card I'm using as a HDD), but couldn't find the bootloader for the installed OS. I hear older slackware releases will boot to terminal from 4mb, and all I wanted to do was play around with IO on the serial/parallel ports anyway.

Win95 was enough of a b!tch to get working.

Anyway, back to superiour architecture, with no windows to clutter the nice second hand PC's I want.