[mythtv-users] AMD Athlon 64 CPUs and MythTV Compiling
tom at compton.nu
Tue Dec 21 00:06:25 UTC 2004
In message <200412202353.41701.doveleys at nildram.co.uk>
Giles Jones <doveleys at nildram.co.uk> wrote:
> On Monday 20 Dec 2004 23:40, Brad Templeton wrote:
> > Sorry, but as I pretty clearly said,the whole clock speed thing _does_
> > matter a bunch on this very specific application -- mpeg encode and decode.
> It's down to the code. If the code doesn't use 64-bit maths then you don't
> quite get the advantage of a 64-bit CPU. Not to mention you really need to be
> running a 64-bit version of Linux.
But you do get the advantage of an extra eight registers, which makes
a huge difference to most code as the x86 architechure is very short on
registers which gives optimisers a very hard time.
I've seen programs which don't do much 64 bit maths go 50% faster just
by recompiling for x64-64.
Tom Hughes (tom at compton.nu)
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