CPUs (cont’d)

$151-$299

Core 2 Duo E6400
Average Overclock: 3395.5

Intel’s Core 2 Duo E6400 and E6300 are proving to be highly popular among enthusiasts on a budget looking for a good CPU upgrade. Unlike the “Conroe” Core 2 CPUs (the Core 2 Duo E6600, E6700, and Core 2 Extreme X6800) these chips don’t ship with a 4MB L2 cache, instead they’re based on Intel’s “Allendale” Core, which features half the L2 cache at 2MB. They also run at slower clock speeds. But other than that, they’re functionally identical to Conroe.

Despite its higher price tag, the Core 2 Duo E6400 slightly gets the nod over the E6300 not so much for its higher clock speed (2.13GHz versus 1.8GHz), but mainly for its higher 8.0x multiplier. So why did we pick the E6400 over the E6300?

Simple: overclocking.

When purchasing lower-end CPUs like the E6300 and E6400, most enthusiasts like to overclock their CPU to get higher performance. Often times you can overclock these low-end processors to run just as fast, if not faster than Intel’s flagship CPUs. With the E6400’s higher 8.0 CPU multiplier, you wont have to hit the high bus speeds like you would on a E6300. To hit 3.0GHz for instance, the E6300 would require a front-side bus speed of 429MHz (7.0x429). That’s an effective FSB speed of 1716MHz! As you can imagine, finding a motherboard to hit such a high FSB speed would be rather difficult.

In comparison, thanks to its higher multiplier, the E6400 would require an FSB speed of just 375MHz to hit 3.0GHz.

In performance benchmarks, the overclocked E6300 would be slightly faster thanks to its higher FSB speed, but you’d have an awfully hard time finding a motherboard capable of hitting 429MHz FSB. Most 975X and P965 motherboards, as well as motherboards based on NVIDIA’s nForce 680i chipset should be up to the task of 375MHz FSB (although this is by no means a given).

At most online retailers, the E6400 sells for about $30-$50 more than the E6300. In our opinion, that’s a small price to pay considering all this.

If you absolutely must stick to $200 or less though, the E6300 would be our top pick.

CPUs $300-$500

Core 2 Duo E6600
Average Overclock: 3382.1

Intel’s Core 2 Duo E6600 is pretty much the CPU of choice for most enthusiasts right now. Why is this particular chip so popular? Because it’s the cheapest Conroe-based Core 2 CPU on the market right now.

With 4MB of L2 cache and a 2.4GHz clock speed, the E6600 has pretty good specs on paper. The real sweet part about the Core 2 Duo E6600 however is that like all Core 2 CPUs, it overclocks like mad! With very little effort, the Core 2 Duo can be overclocked to 3.0GHz, often times at stock voltage. The magic number to hit this speed is 334MHz FSB. At that speed you’ll be running your FSB at 1336MHz and the CPU itself at 3.006GHz. In comparison, Intel’s first desktop CPUs with a 1333MHz FSB won’t be released until the second half of 2007.

With the Core 2 Duo E6600 slightly overclocked, you can experience that FSB speed today.