PPC vs x86 performance comparison

[KennyR]

PPCs are very good at this kind of cache based processing, x86 are very poor. Unfortunately, while I'd love PPC to beat the execrable x86 in speed, it just doesn't. Per MHz it does, obviously...but when was the last time 800MHz was a top end PC? :-(

[KennyR]

if only ibm&motorola would get their ass into gear and start increasing the external bus speed a little
and take advantage of DDR

Nah. The reason they haven't increased the external bus speed is because it doesn't actually make much difference to a PPC, as neither does the RAM speed. A PPC does virtually all of its calculations by loading code from its registers, and there are much fewer load and store operations to external RAM. So increasing the ram speed isn't effective enough to justify the cost.

The x86 needs fast RAM to work properly because of it's legacy design: it just doesn't have many registers and needs to hit that RAM a lot. This will always be the case.

Anyway, having a lot of very fast cache is usually better.

PPC needs a higher clockspeed and an even more optimised logic, and then it could take on the x86. Potentially, you could push a PPC much farther than an x86 - but sadly we'll probably never see it happen. Apple's small market share isn't enough to justify it.

[KennyR]

@Hammer

You raise some interesting points, and you've proven me wrong. I can't argue against your technical knowledge. But, basically the reason I say PPC can be theoretically pushed farther than x86 is because it has no legacy to emulate. The modern x86 has many workarounds for the old 8086 architecture, and yet even the best workarounds have overheads. Tricks and kludges don't make for a very efficient CPU, no matter how well they're done. Granted, that doesn't really matter as things stand, since even with its inefficiencies it's still much faster and will stay that way for the forseeable future.

(And sliding OT, this doesn't really remove the problem of any OS on x86 being unmarketable. Software doesn't sell, hardware does, as I'm sure you know. Any commercial OS would have the threefold problem of coming up against Windows, being pirated like crazy, and being consigned to The Hell of Multi-Boot as a subordinate to Windows or Linux. Until this changes, my x86 bias will remain.)