Peer review of AMD64/FreeBSD article

[Jem Matzan]

Brooks Davis wrote:

>On Fri, Mar 12, 2004 at 08:14:59AM -0500, Jem Matzan wrote:
>  
>
>>Hyper-Threading seemed to help with processes that didn't require a 
>>heavy CPU load. The OpenSSL tests show it being markedly faster in the 
>>smaller algorithms, but lagging way behind the 64-bit Athlon64 when the 
>>serious number crunching comes into play. Intel's press kit shows HT 
>>(and SSE3) giving an advantage when multitasking with four desktop 
>>programs in Windows XP. It's just too hard to show that reliably though. 
>>There's a lot of anecdotal evidence to suggest that AMD64 is faster on 
>>the desktop (in X) in 64-bit mode than the Prescott is in 32-bit, but 
>>I'm having trouble proving it.
>>    
>>
>
>I think it would be a mistake to assume the HT is what accounts for
>the performance difference.  There are so many other architectural
>differences it's hard to see how you could isolate the effects of
>HT.  My suspicition is that better performance on small 
>algorithms is due to them being more or less memory bound (and thus
>similar to the pure synthetic benchmarks).
>
>-- Brooks
>
>  
>
By comparing the Pentium4 to the Athlon64 in i386 mode, you can better 
see the advantage of HT Technology. This is especially evident in the 
OpenSSL tests.

-Jem