On Wed, 2005-11-16 at 09:33, William Yu wrote:
> Alex Turner wrote:
> > Spend a fortune on dual core CPUs and then buy crappy disks... I bet
> > for most applications this system will be IO bound, and you will see a
> > nice lot of drive failures in the first year of operation with
> > consumer grade drives.
> >
> > Spend your money on better Disks, and don't bother with Dual Core IMHO
> > unless you can prove the need for it.
>
> I would say the opposite -- you always want Dual Core nowadays. DC
> Opterons simply give you better bang for the buck than single core
> Opterons. Price out a 1xDC system against a 2x1P system -- the 1xDC will
> be cheaper. Do the same for 2xDC versus 4x1P, 4xDC versus 8x1P, 8xDC
> versus 16x1P, etc. -- DC gets cheaper by wider and wider margins because
> those mega-CPU motherboards are astronomically expensive.
The biggest gain is going from 1 to 2 CPUs (real cpus, like the DC
Opterons or genuine dual CPU mobo, not "hyperthreaded"). Part of the
issue isn't just raw CPU processing power. The second CPU allows the
machine to be more responsive because it doesn't have to context switch
as much.
While I've seen plenty of single CPU servers start to bog under load
running one big query, the dual CPU machines always seem more than just
twice as snappy under similar loads.