AMD64 impressions (Re: AMD64 box)

[David O'Brien]

Matthew Dillon <dillon at xxxxxxxxxxxxxxxxxxxx> wrote:
>     (1) The AMD box is very fast.  Very, very fast.  It blows away everything
>         else hands down.  It is so fast that it spends nearly 1/3 of its
>         time waiting on I/O despite the fact that the I/O requirements
>         for a buildworld are fairly minimal.  It is so fast it makes my P4
>         look like a snail, and even puts my DELL2550 (which is no slouch)
>         to shame.
. ..
> (a) AMD Athlon(tm) 64 Processor 3200+ (2002.57-MHz 686-class CPU)

If you think an Athlon64 is fast, you should get a Tyan Tiger K8S or
Asus SK8N and an Athlon FX51.  The dual-channel memory controller of
the Opteron/FX51 vs. Athlon64 gives a very noticable speedup.


>         The best comparison is the AMD box verse the P4 box.  Both are UP
>         boxes.  The AMD box is 2.1x faster then the P4 box.  If clock speeds
>         scaled, that would make the AMD box equivalent to 2.6GHz P4.  Since
>         clock speeds don't scale, the AMD box is more like a 3.3GHz P4.

:-)

>     (2) The AMD's syscall overhead is very low compared to the P4.
>         I ran the 'sc1' test in /usr/src/test/sysperf.  The AMD box
>         comes back at 242nS/loop while the P4 takes 1300nS/loop and
>         the DELL box (LEAF/SMP) takes 617nS/loop.

We worked on the overall performance of the chip in real-world situations.
Not just paying attention only to those things that raised the MHz and
game FPS benchmarks.

-- 
-- David    (obrien at xxxxxxxx)