Like the Phenom X3 CPUs, which are cut-down Phenom X4s with one of the four cores disabled, Phenom II X3s are cut-down Phenom II X4s.
The first Phenom II X3 to hit the market is the 720 Black Edition. It's clocked at a respectable 2.8GHz and has 6MB of Level 3 cache, the same specifications as the more expensive Phenom II X4 920, but as it has only three cores, each core receives a slightly higher proportion of cache than the four cores of the 920. AMD also plans to release a cheaper Phenom II X3, the 710, clocked at 2.6GHz.
Unlike most Phenom IIs, the 720 Black Edition is a Socket AM3 processor, so its integrated memory controller supports both DDR2 and DDR3 memory. Socket AM3 is pin-compatible with Socket AM2+, but as none of the motherboards in our lab would POST with the 720 Black Edition installed, we had to test it in a Socket AM3 motherboard with dual-channel DDR3. This is a serious problem for AMD, as Socket AM3 motherboards and DDR3 are much more expensive than Socket AM2+ motherboards and DDR2. AMD has also failed to announce or release any high-frequency Socket AM3 Phenom II X4s.
Despite having three cores, the 720 Black Edition performs significantly better than the more expensive quad-core Phenom X4 9750, scoring 980 in our Media Benchmarks compared to 858. It's also 3-7fps faster in games. Priced at £123, the 720 Black Edition falls midway between the £94 Core 2 Duo E7300 and the £142 Core 2 Duo E8400. The 720 Black Edition's third core gives it an advantage in media encoding applications, as it sped past the E7300 in our Media Benchmarks, which scored 900. While you'd have to buy an E8400 to beat the 720 Black Edition in our Media Benchmarks, the E7300 is faster than the 720 Black Edition in games.
As it's a 45nm CPU, the 720 Black Edition overclocks much better than the Phenom X3s. Its CPU multiplier is unlocked, and by raising its vcore to 1.566V, we overclocked it from 2.8GHz to 3.7GHz, boosting its Media Benchmarks score to 1,192. However, the cheaper E7300 easily reached 4.2GHz, and scored 1,433 - more than the £187 Phenom II X4 940 Black Edition.
If BIOS support for Socket AM3 processors in Socket AM2+ motherboards is imminent, the 720 Black Edition and forthcoming 710 could present a serious challenge to the Core 2 Duo in the value-driven £100-£125 CPU market. However, thanks to recent aggressive price cuts on the Core 2 Duo E8400 and E8500, Intel's faster, more overclockable and more energy-efficient chips should still be at the top of your list.
Author: James Gorbold & Antony Leather
Custom PC Online