Nearly £150 for an extra 200MHz. If you're of the opinion that that sounds like a pretty rum deal, then join the club. Unlike its Extreme Edition sibling, the E6700 can't even claim to offer the dubious benefit of an unlocked CPU multiplier.
Consequently, it offers the same great dual-core feature set, including 4MB of shared cache memory, monstrous integer and SSE performance and modest operating temperatures as the cheaper E6600.
What it doesn't deliver is a tangible advantage in terms of headroom, topping out at just over 3GHz. Of course, mileages vary when it comes to overclocking and you can expect an E6700 to clock higher than a E6600. But not by much.
We reckon you'll get more performance for less by buying an E6600 with high quality cooling and a good motherboard.