SSE2 makes Opterons slower than Athlon XPs

[Adul]

http://www.theinquirer.net/?article=9278

Taken with a grain of salt

 

[miken]

One persons findings doesn't make it true, especially with Sisoft Sandra.

 

[MikeMike]

But it's not all bad news for the Opteron. He said that well known Japanese archiving software GCA (http://www.emit.jp/gca/gca.html) compresses WAV files a staggering 50% faster than P4-2.8GHz, equivalent to a Pentium 4.4GHz chip, if such a beast existed.

Wow all japanese software. Yeah one persons findings dont mean anything.

 

[godmare]

Seems to me that testing (and judging) the Opteron as a workstation processor is a bit premature, on top of using 32-bit software. Athlon64, while still a 64-bit chip will undoubtedly be optimized for orkstations, having all the wrinkles of the Opteron ironed out.

 

[andreasl]

Comments from someone who actually knows this stuff

 

[pm]

Nice link, andreasl. Thanks

 

[Diable]

He told the INQUIRER that he measured the execution time to encode DV-format AVI files to MPEG, WMV, Divx and Xvid. He found that for encoding DivX and Xvid, Opteron 242's performance is roughly equivalent to a Pentium 4-2.8GHz, which matches the expectation from SPEC int/fp results.

This guys numbers seem funny, I've never seen a AMD processor (of any kind) hang with a P4 in Divx/Xvid encoding. In Anand's tests a 1.8GHz Opteron did 69.5fps when encoding using Divx5 (link) and a 2.8GHz P4 did 80.5fps (link).

 

[imgod2u]

What I'm curious about is whether this is an Opteron-specific issue. Did he try disabling SSE2 on the P4 and seeing how well it ran with MMX? Perhaps SSE2 is just not good at integer math. It is a floating point extension after all......

 

[zephyrprime]

Did he try disabling SSE2 on the P4 and seeing how well it ran with MMX?

That's not how it works. SSE code is SSE code and MMX code is MMX code.

 

[imgod2u]

Yes, but the specific program he's refering to has two sets of code, one that uses SSE2 and one that only uses MMX. He was able to disable the usage of SSE2 for the Opteron and use MMX instead.