AMD Phenom II X4 955 Black Edition review

Seth Barton
24 Jun 2009
Our Rating 
Price when reviewed 
inc VAT



PCs with Phenom II processors have proven to be great value in recent group tests.

This is largely because they're compatible with inexpensive AM2+ motherboards and DDR2 memory, which keeps overall costs down. The X4 955 Black Edition is the fastest Phenom II yet, running at 3.2GHz.

It has a similar architecture to the X4 920 but is also compatible with the newer AM3 socket. This means it can be used in both DDR3-based AM3 motherboards and DDR2-based AM2/AM2+ boards (but check your board's latest BIOS update first). This flexibility sounds useful, but the performance gains from using more expensive DDR3 memory are small. The Black Edition name signifies that the chip has an unlocked multiplier, so it's easier to overclock.

In our new benchmarks the chip was visibly quicker than the X4 920. It's 12 per cent faster than the X4 920 overall, but it costs around £60 more. It may be fast, but it still can't compete with even the slowest Core-i7 chip.

The AMD Phenom II X4 920 strikes a better balance between performance and value. We'd only recommend the X4 955 to those who want the fastest upgrade for their AM2/AM2+ PC.

Basic Specifications

Processor coreDeneb
Processor clock speed3.2GHz
Processor socketAM3
Processor process45nm
Processor number of coresfour
Processor supported instructionsMMX, SSE, SSE2, SSE3, SSE4a, Enhanced 3DNow!, NX bit, AMD64, Cool'n'Quiet, AMD-V
Processor multiplierx16
Processor external bus200MHz (2GHz HyperTransport)
Level 1 cache4x 128KB
Level 2 cache4x 512KB
Processor level 3 cache6MB
Supported memory typeDDR2 667/800/1066, DDR3 800/1066/1333
Processor power rating (TDP)125W


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