Re: Opteron vs. Xeon performance differences

On Fri, 10 Oct 2008, Bart Grantham wrote:

> The Opterons are 2220 SE's, the Xeons are 5450's I think (family "15", model "6").
>
> Xeon - 3056 MB in 2.00 seconds = 1527.85 MB/sec
> Opteron - 4944 MB in 2.00 seconds = 2472.50 MB/sec

There's something wrong with that Xeon system. That number should be
twice that and your Xeon smoking those Opterons by 25% or so on
benchmarks. My Q6600 system at home has a slower bus and clock speed than
your Xeon, but hits 3891MB/s on cached hdparm even with the slowest of the
RAM I have here. Now that I got the first round right, can I make a
double or nothing bet that your Xeon system is either a) not running your
RAM in dual-channel mode or b) is getting throttled by power management?

> Should I cross post to pgsql-performance? Or are most of the people on
> that list here, too?

That would have been a better place to start at, but don't bother
switching now--there's a lot of overlap. Cross-posting to the lists here
is bad, partly because then replies by people who only belong to one of
the two end up bugging the list admins. One of these days I'm going to
summarize the main lore on this topic into a Wiki article anyway, which
will pull the good stuff out of here regardless of the originating list.

--
* Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD