AMD - Athlon 64 FX-62 and Socket AM2 review

With the launch of Athlon 64 FX-62, AMD has also rolled out its new AM2 platform. This is a move from Socket 939 and Socket 754 to a new processor socket which has 940 pins. That number may sound familiar, but this isn't the same 940-pin layout that is used by the Opteron server processor, hence the name AM2 rather than a number.

AMD is changing its entire range of desktop processors over to AM2, from the highest Athlon 64 X2 to the lowest Sempron. The reason for the change is that AMD has decided that the time is right to shift from DDR system memory to DDR2, which is the same type of memory that Intel started to use with the LGA775 version of Pentium 4.

At that time, DDR2 was relatively slow and had horrendous latency (lag) but Intel was determined to pursue clock speeds that went beyond 4GHz so it needed memory that could provide adequate bandwidth. AMD is in a different position as it has raised clock speeds quite slowly from the initial 1.6GHz of the first Opteron to 2.6GHz with FX-60, and it's only now, with the 2.8GHz of FX-62, that it feels the need for DDR2. Well, that and the fact that 800MHz/PC2-6400 DDR2 is now fast enough to offset the latency problem.

You need to make sure that you choose memory that is fast enough to support your new AM2 processor, so here is a short list of recommended configurations:

AM2 Athlon 64 FX-62 with DDR2-800/PC2-6400 or DDR2-1066/PC2-8500
AM2 Athlon 64 X2 with DDR2-667/PC2-5300 or DDR2-800/PC2-6400
AM2 Athlon 64 and Sempron with DDR2-533/PC2-4200 or DDR2-667/PC2-5300

The other physical change is that the AM2 heatsink frame mounts through four holes on the motherboard, compared to the two holes used by Socket 754 and 939, but ironically the same as the Socket A Athlon circa 2001. The AM2 heatsink attaches to the frame with two clips, rather than the six clips used on the earlier version, and while this looks like a backward step we doubt that it will cause any problems.

Athlon 64 has the memory controller integrated within the processor rather than the motherboard chipset, so there was no need for any dramatic change to the new wave of motherboards apart from a change in processor socket and the memory slots. Indeed, ATi's Radeon Xpress 3200 chipset supports both the old and new Athlon 64, but Nvidia has decided to roll out a new family of chipsets for AM2 called Nforce 500.

There are currently four members of the family with the fully-featured Nforce 590 SLI at the top of the tree, Nforce 570 SLI in the mid-range, Nforce 570 below that and Nforce 550 so far down the pecking order that you'd be better off with Nforce 4, if you were given the option.

The 590 SLI has a pair of graphics slots, each with 16 PCI Express lanes, just like the Nforce4 32 chipset. In total 590 SLI supports 46 lanes of PCI Express. In addition it has LinkBoost which will automatically overclock the graphics buses when you plug in 'compatible' graphics cards, which currently means the GeForce 7900GTX.

You also get a pair of Gigabit LAN ports which can be combined with DualNet to give the equivalent of a 2Gbps connection, while FirstPacket prioritises your Internet traffic so Counter Strike doesn't suddenly fall foul of Windows Update or some other horror.

This is a good idea, but we find the biggest problem with Windows in respect of Internet traffic is that an application such as e-mail or your firewall will grab the Windows focus and present a pop-up that has to be dealt with. If you're gaming in full-screen mode, the pop-up can either kill your game or it can remain invisible behind the game yet still demand attention.

On the subject of firewalls, Nvidia has dropped the hopeless ActiveArmor firewall that it introduced with Nforce4. And every member of Nforce 500 supports Intel's Azalia HD audio.

Nforce 570 SLI supports 28 lanes of PCI Express with x16 for a single graphics card or dual x8 for each graphics card in SLI, just like Nforce4 SLI. It doesn't support LinkBoost but it does have FirstPacket and DualNet. The Nforce 550 doesn't support any of the new technologies, which effectively makes it an Nforce4 with support for AM2 processors.

So, what is the upshot of the move from Socket 939 to AM2? Well, naff all really.
The previous king of the performance charts was the Athlon 64 FX-60, which uses Socket 939 and runs at 2.6GHz on dual channel DDR memory. The new FX-62 runs at 2.8GHz and has exactly the pro rata performance increase that you would expect from the extra 200MHz, which means that the new Socket, new chipset and the change to DDR2 memory have precisely zero effect.

That's not to say that Nforce 570 SLI is a failure, as it has enormous potential in a high-end gaming PC with a pair of GeForce 7900GTX graphics cards, provided you have the necessary £3,000.