Re: Two identical systems, radically different performance

On 09/10/12 12:40, Craig James wrote:
> Nobody has commented on the hyperthreading question yet ... does it
> really matter? The old (fast) server has hyperthreading disabled, and
> the new (slower) server has hyperthreads enabled.
>
> If hyperthreading is definitely NOT an issue, it will save me a trip
> to the co-lo facility.
>
> Thanks,
> Craig
>
> On Mon, Oct 8, 2012 at 3:29 PM, Craig James <cjames(at)emolecules(dot)com
> <mailto:cjames(at)emolecules(dot)com>> wrote:
>
> One mistake in my descriptions...
>
> On Mon, Oct 8, 2012 at 2:45 PM, Craig James <cjames(at)emolecules(dot)com
> <mailto:cjames(at)emolecules(dot)com>> wrote:
>
> This is driving me crazy. A new server, virtually identical
> to an old one, has 50% of the performance with pgbench. I've
> checked everything I can think of.
>
> The setups (call the servers "old" and "new"):
>
> old: 2 x 4-core Intel Xeon E5620
> new: 4 x 4-core Intel Xeon E5606
>
>
> Actually it's not 16 cores. It's 8 cores, hyperthreaded.
> Hyperthreading is disabled on the old system.
>
> Is that enough to make this radical difference? (The server is at
> a co-location site, so I have to go down there to boot into the
> BIOS and disable hyperthreading.)
>
> Craig
>
>
My latest development box (Intel Latest Core i7 3770K Ivy Bridge Quad
Core with HT 3.4GHz) has hyperthreading - and it *_does_* make a
significant difference.

Cheers,
Gavin