Subject: Re: [linux-audio-user] amd vs p4
From: Steve Harris (S.W.Harris_AT_ecs.soton.ac.uk)
Date: Wed Feb 18 2004 - 11:43:15 EET
On Wed, Feb 18, 2004 at 01:33:36 +0100, Tim Blechmann wrote:
> hi all,
>
> i'm curious about your thoughts about the recent generation of amd's
> 64bit chip and the p4 ...
> it seems, that the amd chip isn't as fast as the p4 if you compare the
> floating point performance (what's essential for dsp), but on the other
> hand it doesn't suffer from the denormal bug (and several pd / ladspa
> object still suffer from denormal problems)
I'm not up-to-date on benchmarks so I cant comment, but just to clarify
the denormal thing in P4's is not a bug, its how you handle denormals, the
only difference is that the P4 takes longer to handle them so you get away
with it less often.
Ideally DSP software would be written so that it never generates them,
but, erm, well, developers are lazy, y'know :)
On the P4 its possible that you can set some flags to use SSE instructions
instead of 387 and tell the SSE unit to never produce denormals, but
last time I tried it, gcc 3.something generated bad code (illegal
instructions).
- Steve
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