Re: Performance on new 64bit server compared to my 32bit desktop

Scott Carey wrote:
> But the select count(*) query, cached in RAM is 3x faster in one system than the other.  The CPUs aren't 3x different
performancewise.  Something else may be wrong here. 
>
> An individual Core2 Duo 2.93Ghz should be at most 50% faster than a 2.2Ghz Opteron for such a query.   Unless there
aresome compile options that are set wrong.   I would check the compile options. 
>

Sure, it might be.  But I've seen RAM on an Intel chip like the E7500
here (DDR3-1066 or better, around 10GB/s possible) run almost 3X as fast
as what you'll find paired with an Opteron 2427 (DDR2-800, closer to
3.5GB/s).  Throw in the clock differences and there you go.

I've been wandering around for years warning that the older Opterons on
DDR2 running a single PostgreSQL process are dog slow compared to the
same thing on Intel.  So that alone might actually be enough to account
for the difference.  Ultimately the multi-processor stuff is what's more
important to most apps, though, which is why I was hinting to properly
run that instead.

--
Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us