It’s been two years since Intel has made the transition from DDR to DDR2 memory. The initial transition to DDR2 showed very little benefit due to the increased access latency, higher costs, and slow initial speeds thus AMD sat idly by and stuck with good ole tried and true DDR400 memory. DDR2 has improved quite a bit since the initial introduction two years ago. Speeds have increased to 800 MHz with 1066 MHz enthusiast memory modules available and prices have dropped well below DDR400 prices. Latencies have also become manageable and offset by the increased frequencies too.
Although AMD has tried its best to keep DDR memory alive for the past couple years it was only a matter of time before AMD made the switch to DDR2. The downside is the move to DDR2 comes with a brand new socket, motherboards, though existing Socket 939 compatible chipsets can be adopted for the new socket. Nonetheless, with progress come changes and new hardware requirements. Enter Socket AM2, AMD’s new DDR2 touting socket for Athlon 64, Athlon 64 X2, Athlon FX, and Sempron processors.
This time around AMD has opted to unify Athlon and Sempron processors to a single socket and platform unlike the existing Socket 939 and 754 separations. Instead of only launching high end models, which is typical for most new processor launches, AMD is launching a whole top to bottom lineup of socket AM2 compatible processors. These processors include a top of the line Athlon FX-62, 3800+, 4000+, 4200+, 4400+, 4600+, 4800+, and 5000+ X2’s, 3500+, 3800+ Athlon 64’s, and lastly 3000+, 3200+, 3400+, 3500+, 3600+ Sempron processors.
Processor configurations are the same with the socket 939 counterparts, though the FX-62, X2 5000+ and 4000+ are new for socket AM2. Cache sizes for the FX-62 is 1MB like previous Athlon FX’s while X2’s come in either 512KB or 1MB cache sizes like the socket 939 counterparts. There is no pricing differentiation with socket AM2 and socket 939 processors either, with the exception of the new X2 4000+, 5000+, and FX-62 so those that can’t decide between socket 939 and AM2 can pick either without paying any premiums for either processors.
Socket AM2 and 939 Differences
While all socket 939 processors supported DDR400 memory socket AM2 processors differ a little in the memory support department. All single core Athlon 64 and Sempron processors will support up to DDR2-667MHz. The more performance oriented Athlon 64 X2 and Athlon 64 FX support DDR2-800Mhz for increased performance, though its backwards compatible with slower DDR2 speeds as well. AMD has also added Pacifica hardware virtualization technology to compete against Intel’s Vanderpool hardware virtualization technology too.
With a new socket comes a new heatsink mounting mechanism. Socket AM2 uses a new 4-bolt mounting tray compared to socket 754/939/940’s 2-bolt mounting tray. AMD claims the new mounting tray increases heatsink stability. Those that have existing socket 939 compatible heatsinks that mount using the mounting tray should have no problems using the same heatsinks on socket AM2 as long as it can withstand the heat. Heatsinks that required removing the mounting tray will most likely require new mounting gear.
Aside from the obvious memory differences and a new heatsink mounting tray there isn’t much difference between socket 939 and socket AM2 processors.
Athlon 64 X2 5000+
AMD sent us Athlon 64 X2 5000+ sample for our socket AM2 evaluation. The processor is clocked at 2.6 GHz with 512KB of L2 cache per core (1MB total) which is similar to the Athlon FX-60, though with half the L2 cache. It’s hard to tell the difference between sockets AM2 (left) and socket 939 (right) processors. The heat spreader is marked the same and the only way to differentiate the two processors is socket AM2 processors are denoted as revision F processors. If the third line down from name branding starts with an F, you have a socket AM2 processor.
Flipping the processors over reveals a few noticeable pin-out differences. With both processors facing the same direction, according to the heat spreader plate, it appears socket AM2 (left) and socket 939 (right) are keyed differently. Socket AM2 also has 940 pins too so don’t expect to mistakenly install a socket AM2 processor in a socket 940 compatible motherboard as its impossible without a hammer.
