Re: Two identical systems, radically different performance

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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@xxxxxxxxxxxxxx> wrote:
One mistake in my descriptions...

On Mon, Oct 8, 2012 at 2:45 PM, Craig James <cjames@xxxxxxxxxxxxxx> 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

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