RE: [Xen-users] Xeon 5160 vs 5080

["Steffen Heil" <lists@xxxxxxxxxxxxxxx>]

Hi

> Chip          Clock           HT      Cache   Bus Speed
> ---------------------------------------------------------
> 5080          3.7 GHz         YES     2MB     1066 MHz
> 5160          3.0 GHz         NO      4MB     1333 MHz
> 
> Does the .7 GHz and HT worth more then 4MB cache and higher 
> bus speed? The application is VoIP so there is not a lot of 
> IO so I would not think Bus Speed would matter. I am finding 
> mixed information on HT, some say it is great, others say it 
> actually slows things down, could this be why the new chips 
> done have HT?

Hyperthreading is only bad in a few cases. One of the I heard a lot about
was running *old* versions of interbase with hypertheaded CPU, where the
"one-process" design of interbase in conjunction with the required locks
lead to the problem of having the process "jumping" between the virtual
cores, taking about all the CPU load for nothing. The solution in that time
was to disable Hyptertheading OR to set affinity to one cpu only. (Current
builds don't have that problem as they use NPTL.)

However by bet is that the 5160 will outperform the 5080 for it's 4 MB cache
alone!
(Yes running virtual hosts does benefit from more "virtual cores", but those
also need to share the cache...)

Regards,
  Steffen

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