XBitLabs recently reviewed the upcoming low-end Penryn quad Q9300.
They spent more than a bit of time trying to overclock it, and found that they were rather constrained by the chip’s low (7.5X) multiplier and high (333MHz) FSB.
Faced with an FSB wall of about 470MHz, they were only able to get the Q9300 to about 3.5GHz.
In contrast, they were able to get the dual-core E8500 (with a 9.5X multiplier) to 4.3GHz, or over 20% faster.
This means the overclocked dual-core beats the quad in any app/game that makes little or no use of the additional cores. This is quite often the case for games.
Yes, the Q9300 is the low-end quad; there will be a slightly faster 2.66GHz (8X333) processor available for $50 more, but that will only reduce the GHz gap from over 20% to about 15%.
Of course, if the app/game does make good use of all four cores, four slower cores beats two quicker ones.
Obviously, what’s best for you depends on what you do, but if you don’t consider that, and you don’t do 4-core kind of things, you could pay more and effectively get less.
You may find owning a quad under those circumstances more “prestigious,” but what are you more interested in, show or go?
If you seriously want both, you’ll need to maybe wait a bit and pay a bit more attention to the motherboard you get with the quad. XBitLabs goes into quite a bit of detail into desirable BIOS features, the ability to cool the NorthBridge easily, items that will help you maximize FSB.
Of course, maximum FSB will likely improve in time with new motherboards.
Until they do, though, Penryn quads will likely require more care and feeding than usual, but still not quite hit their maximum potential.