P4s, Athlons and bandwidth

[Alan Cox]

> processor is the PIII.  However documents in AMD's web site show
> that moving data (ie memcpy and friends) can be made several times
> faster if using 3DNow instructions and data prefetching, I gave only

Sometimes and for some situations. Most string ops are on short strings
so actually don't benefit from fancy stuff like mmx because of the
overheads (in the kernel we dont even try and do fancies until we
are copying 1K or so)

Alan