Purchasing the correct hardware: dual-core intel? Big cache?

[Bill Moran]

On Tue, 25 Apr 2006 07:56:03 -0500
Derek Ragona <derek at computinginnovations.com> wrote:

> Yes, dual core is on average 20% faster than hyperthreaded CPU's.  But that 
> is general benchmark.  The range of performance difference is 10% - 30% 
> depending on the application mix.

Thanks.

> If you use well optimized applications, you see the larger performance 
> gain.  Poor optimization causes a CPU to chug along, flushing the CPU cache 
> often, and slowing things down considerably.

I know.  That's why I'm so desperately trying to find a way to determine
how often the cache is being invalidated - so I can determine whether
larger cache sizes (such as 8M) are worthwhile.

The database server is PostgreSQL.  If we find optimization problems
with it, we'll definitely work with the PostgreSQL folks to get those
problems addressed, but I'm not expecting a lot of poorly-written code
in something as mature as PostgreSQL.  So, making a (reasonable)
assumption that PostgreSQL is well-optimized, I need a way to tell if
adding another 6M of cache will improve performance, _before_ we pay
for it.

That's my question.

-- 
Bill Moran
Collaborative Fusion Inc.

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