AMD Phenom II review

The latest addition to AMD's range of processors is the Phenom II.

It's built on a 45nm die rather than the original Phenom's 65nm, which makes it cooler, faster and less power-hungry than standard Phenom processors running at the same speed. Like the original Phenom series, the Phenom II's four cores share an L3 cache, which has been expanded to 6MB, along with 512KB of L2 and 128KB of L1 cache per core. These caches should reduce the number of times the processor has to access comparatively slow system memory.

Unlike Intel's Core i7 processors, which are a completely new technology and will need a new motherboard with DDR3 RAM, AMD's Phenom II is backwards-compatible and will work in existing AM2+ motherboards. This means that upgrading to Phenom II is as simple as switching processors. It will also work with the socket AM3 boards due for release later this year, which will support both DDR2 and DDR3 memory.

Phenom II processors are designed to work best with motherboards that use AMD's latest 790 Northbridge and SB750 Southbridge chipsets. We used MSI's DKA790GX Platinum, which uses these chipsets, to test all our AMD processors.

Specific processors

The current Phenom II range includes just two processors, the 2.8GHz X4 920 and the 3GHz X4 940. The 940 has an unlocked multiplier, which makes it easy to overclock without affecting the HyperTransport or memory speeds. AMD reports that it has managed to push it up to 3.9GHz in an air-cooled system and a whopping 6.3GHz in a system cooled by liquid nitrogen. In the real world, few of us have the time or money to go to such extremes but, like the Phenom Black Edition processors, the 940 should gain plenty of fans among hardcore gamers and overclockers.

However, with a processor this fast, overclocking isn't even necessary for most users. This is why we favour the Phenom II X4 920, which at £190 is great value for the power it provides. It wins our coveted Ultimate award.

One of the main advantages of Phenom II processors is that you can gradually upgrade your system, first buying your new processor to use with an older AM2+ board before upgrading the motherboard and RAM when you can afford it. This is in sharp contrast to the immediate expense of buying a new Intel Core i7 processor, motherboard and DDR3 RAM. Although the Phenom II can't rival the power of the Core i7 chips, it's still incredibly powerful and significantly cheaper.