Remember when a quad-core PC processor seemed exotic, if not downright decadent? We can. It was only a couple of years ago. Today, the AMD Athlon II X4 620 is yours for under £70. By Grapthar's Hammer, what a savings.

The startlingly low price is possible because AMD has cooked up a special new quad-core die for all Athlon II X4s. Instead of taking the existing Deneb die from its Phenom II X4 chips, such as the 965 Black Edition, and disabling a few features, the new Propus die is purpose built to deliver four cores for less cash.

The good news is that the only significant change has been the loss of Deneb's 6MB L3 shared cache memory pool. Instead, Propus-based chips like the Athlon II X4 620 must make do with just 512k of L2 cache per core.

The 620's super-low price also reflects its modest 2.6GHz clockspeed. Put it all together and you have an intriguing quad-core chip that's actually cheaper than the triple-core AMD Athlon II X3 435. As for Intel's processors, the dual-core Core i5 661is over twice as expensive.