Review: AMD Phenom X4 9850 Black Box Edition

The original 9000-series Phenoms received bad press since, at launch, AMD admitted the Phenom’s translation lookaside buffer (TLB), which maps virtual addresses onto physical addresses, was faulty in the L3 cache. The upshot is a 9000-series can crash when all four cores go to 100 per cent load.

Initially we recommended holding off Phenoms until further investigation, but we can now confirm the bug only affects server applications. We’ve not found a consumer benchmark or program that can cause the Phenom to crash. Despite this, AMD has released its 9050-series of Phenoms, which don’t have the TLB bug and the bad press associated with it.

At 2.5GHz, the X4 9850 Black Box edition is the fastest TLB bug-free Phenom and 100MHz faster than AMD’s previous best, the Phenom X4 9700. The Hypertransport 3.0 link and memory controller are increased to 4GHz (full duplex) and 2GHz respectively (a Phenom 9750/9550’s Hypertransport link will only run at 3.6GHz, memory controller at 1.8GHz).

Like all Black Box edition processors, the CPU multiplier is unlocked, giving it maximum overclocking potential. AMD’s Overdrive utility lets you do this in simple fashion, but we found it unstable for serious performance gains. Using the Bios we overclocked the 9850 to 3.1GHz with a 0.225V core increase.

At 2.5GHz the 9850 is slower than Intel’s slowest 2.4GHz Core 2 Quad, the Q6600, by four per cent in PCmark05’s CPU test and by six per cent Cinebench 9.5. When overclocked to 3.1GHz it sped past the Q6600 and the QX6700, scoring 9,172 in PCmark05.

If you’re building a home-theatre PC, pairing this Phenom with Gigabyte’s 780G motherboard makes a great value package. But for high-end PCs, Intel remains king.