AMD Phenom II X4 955 Black Edition CPU

Comparative Cost

According to AMD the Phenom II X4 955 is set to retail at around $245, or £210. Comparatively this puts it well ahead of other AMD CPUs - the closest is the Phenom II 940 at £167.89 or $189.99 but it's AM2+ only, and Intel CPUs around the same money are the:

• Core 2 Duo E8600 at £224.70 or $269.99
  
• Core 2 Quad Q9550 at £201.19 or $269.99
  
• Core 2 Quad Q9400 at £185.08 or $219.99
  
• Core 2 Quad Q6700 at £142.22 or Q6600 in the US for $214.99
  
• Core i7 920 at £237.10 or $279.99

According to the graphs, in very lightly threaded applications, the Intel Core 2 Duo E8500 triumphs, so the E8600 will be even better simply due to its extra clock speed. However, even in gaming we're seeing the quad cores like the Phenom II X4 955, Core i7 920 and Core 2 Quad Q9550 top the table with a mixture of MHz and spare resources - a trend that will inevitably continue.

Despite the 500MHz+ core clock speed deficit, the Core i7 920 still triumphs the Phenom II X4 955 in most of the tests. This is especially true in highly threaded ones thanks to its virtual eight cores from HyperThreading and three channels of DDR3 affording somewhat more bandwidth, in addition to the inherently wider core execution engines that can crunch data faster.

The 955 fritters between a close second and some way far behind, but it is still cheaper by $25/£30. Both are "125W TDP" parts (AMD and Intel measure TDP differently) but we still find the Phenom IIs need significantly more cooling than their Intel counterparts to achieve the better overclocks. 600MHz extra from the 955 is pretty weak with all things considered, as the 2.67GHz Core i7 920 will often see 4GHz with very little effort.


Let's also consider platform cost too, since every set up above is different - Core i7, AM3 and Core 2. How does this affect the overall upgrader's bottom line?

Well, Core i7 is not as expensive as you'd think, with motherboards and memory dropping quite sharply in price since when they were launched. The Gigabyte GA-EX58-UD3R is just £154 now, and 6GB of 1,333MHz DDR3 memory can be purchased for £64. Together, the kit with a retail Core i7 920 at £240 will cost £458.

On the Core 2 Duo side of things, the motherboards are slightly cheaper at £110 for example, then coupled with some £40 4GB kit of DDR2 1,066MHz (like everyone, we wouldn't bother with DDR3 for Core 2) and the we're looking at about £380 for the E8600 setup, £366 for the Q9550 setup, £338 for the Q9400 setup and £302 for the Q6600 G0 system too.

In comparison, the AMD system will cost £210 for the CPU, £54 for 4GB of 1,333MHz DDR3 and £154 for the MSI 790FX-GD70 (our current favoured AM3 overclocking board). In total that equates to £418 - not that cheap - but if you substitute the motherboard with a 790GX that comes to a far more competitive £379. In terms of AM2+, we'd only be saving another £15 between the difference of DDR2 and DDR3 as the motherboards are about the same, so that makes £405 and £364, which is still more than a Q9550 setup.

On the face of it, we're abound with high quality processors and for the first time in the £160 to £240 (or $200 to $300) segment, you can buy a quad core AMD or Intel CPU that delivers top performance and doesn't cost the earth. However, we're still torn on deciding whether or not the 955 is any more than a good one. The Phenom II X4 940 is now £168, which is significantly cheaper and doubled with very capable and very inexpensive 1,066MHz DDR2 this setup comes to a shade over £350 - over £50 less than the AM3 setup. But no more Phenom AM2+ CPUs are being released, very few new AM2+ motherboards are being designed and AM2+ CPUs are not forward compatible to AM3: therefore offering no upgrade path. The same could be said for Intel, but at least P45 boards are still being refreshed and released until well into late Q3 or Q4 this year.

In our experience it's easier to get more from a cheaper Intel P45 motherboard than it is a cheap AMD one, so in that respect while the 955 generally out performs the Q9550, a Q9550 setup we'd consider buying is also quite a bit cheaper. But if you are going after the performance argument, why not drop another £40 and buy a Core i7 920, and get an extra 2GB of memory on top too? The performance advantage of the i7 920 is obvious in many of the tests, and only occasionally does the Phenom II X4 955 BE get close or in just a single case, exceed it.

Final Thoughts

The bottom line is that with the Phenom II X4 955 Black Edition, like the 940, AMD has developed yet another great processor and more importantly positioned it competitively in an area that needed it. It's not the definitive choice - we still think crucially the overclocking is limited for air coolers - and in fact we still think the Intel answer is still marginally more favourable. If you don't care about an upgrade path, we feel the 940 is now the favourable AMD choice, due to the fact it has recently dropped in price quite significantly, and the overclock compared to the 955 will likely be the same.

On the other hand, if you're after a fresh system upgrade and were looking at the Core i7 920, then the Phenom II X4 955 or 940 Black Editions should certainly fall within your remit for consideration, but again we'd probably opt for the i7.

However let's also remember AMD's commitment to the true enthusiast - not only has it continually released a range of Black Edition products in all price brackets, but it has continually supported the overclocking community with its ever evolving AMD OverDrive software, rather than knock it on the head like some other manufacturers. While motherboard companies will continue to push their own overclocking software, AMD is creating an environment that others should aspire to - open, affordable and with plenty of options to keep us tinkering. Well done, AMD.

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Score Guide