AMD Phenom II X4 955 Black Edition Review - AMD Phenom II X4 955 Black Edition Review


Starting with the gaming benchmarks, we see quite a mixed bag. While the 955 BE competes very well with even Intel’s most expensive CPUs in Crysis, Enemy Territory: Quake Wars shows a distinct favouritism towards all the Intel CPUs. Nevertheless, the 955 Black Edition still has plenty enough performance to play both games satisfactorily.

Moving onto video encoding and we see a continuation of a trend that’s been going for some time. Intel CPUs are just better at encoding video. That said, the extra clock speed of the 955 BE means it keeps up with its price competitor, the Q9550.

It’s a similar story with 3D rendering. While Intel has a clear lead overall, the 955 BE stays biting at the heels of the Q9550, at least in Cinebench. In POVRay there’s still quite a gulf with the 955 BE taking 1101 seconds as compared with the Q9550’s 841 seconds – a difference of about four minutes.

Our image editing and file compression tests show less dramatic differences between all the various CPUs but nonetheless there’s still a general trend towards Core i7 and Core 2 beating AMD’s best. Once again, though, when we talk about price competitors, the 955 BE and Q9550 are within spitting distance of each other. A trend that is finally played out to completion in our final tests; encoding mp3s.

Overall, then, it’s actually the Q9550 looks like being the best bang for buck at the moment, just. However, there’s still that all important overclocking potential to take into consideration. Unfortunately things didn’t go all that well for us.

Essentially, we needed to update our test motherboard’s BIOS to get it to correctly recognise the 955 BE. However, this beta BIOS was so unfinished it refused to store any changes we made to the BIOS settings. This meant we couldn’t change things like the boot drive order, etc. This was a bit of a pain but the board worked and gave seemingly valid results so we soldiered on (bear in mind the operating system and drivers for the board were already installed on our test hard drive).

When it came to overclocking, though, we used AMD’s overdrive utility to up the multiplier from 16x to 19x and the system crashed. So we tried 18x instead and this worked fine. Not yet wishing to up any voltages we next tried 18.5x and the system crashed. Unfortunately this resulted in a corrupt operating system, which meant we needed to run a repair installation, but of course we couldn’t change the boot settings to make the system boot from a CD.

As we leave overclocking until relatively late in the day we didn’t have time to fully get to the bottom of how we could fix this problem so we’ve had to rely on the initial figures we recorded with the CPU running at 3.8GHz. At this level the CPU seemingly consumed no more power than at stock speed and was completely stable and its multithreaded Cinebench score went up from 10461 to 11368 (an eight per cent improvement).

In contrast we were able to up the FSB on our Q9550 from 333MHZ to 400MHz without any extra voltage, taking our 2.8GHz chip to 3.41GHz in one easy step. This resulted in its Cinebench scores going from 11068 to 12676 (a 14 per cent improvement).

All told, then, the Black Edition moniker is not necessarily the be all and end all. That said, this is still a very competitive CPU and is one you should certainly consider.


In the Phenom II 955 Black Edition, AMD has created a great CPU that will satisfy the vast majority of power users, gamers, and enthusiasts. Most importantly, it’s priced very competitively and makes for a great alternative to all of Intel’s solutions at around the £200 price point. However, the apparent overclockability of these chips due to their unlocked multiplier doesn’t actually hold out in normal circumstances. Perhaps if you use water cooling or liquid nitrogen you’ll be able to get this chip running at 6.0GHz (like people have with the Phenom II X3 720 Black Edition) but in a conventional air cooled system you’re just as likely to get the same amount of overclocking headroom from one of Intel’s chips.

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