The AMD Athlon64 3800+ processor follows in the footsteps of its popular 32/64-bit siblings, and proves itself well in the benchmarks as we'll soon see. Built on the same 0.13 micron manufacturing process as earlier Athlon64 CPUs, the Athlon64 3800+ marks the point when AMD transitioned from a 754-pin package to 939 pins. The chip we'll be testing out in this review is based on the 'Newcastle' core, and runs at a very nice speed of 2.4 GHz.

The Athlon64 3800+ uses an organic FCPGA packaging as opposed to the ceramic found on Athlon64 FX chips. From the top, the Athlon64 3800+ looks identical to the Athlon64 3200+. On the bottom of the processor, it is simply filled with pins, although this shouldn't be a surprise considering the amount of pins in the new socket 939 package.

Along with the introduction of the Socket 939 Athlon64 3800+, AMD also released the Socket 939 Athlon64 3500+ (2.2 GHz) and moved its high end Athlon64 FX-53 (2.4 GHz) over to the Socket 939 platform. Subsequent processors have since been released for both the Athlon64 and Athlon64 FX, but the 3800+ was the first to make the transition.

With both mainstream Athlon64 and high end Athlon64 FX processors using the 939-pin socket, and dual channel DDR memory, AMD had to figure out a new way of differentiating them. If you remember, the main difference between Socket 754 Athlon 64 and Socket 940 Athlon64 FX was the dual-channel memory that the FX had.

AMD Athlon64 3800+ Processor Includes: Warranty, instructions

This time around AMD has cut the L2 cache in half for Socket 939 Athlon64 CPUs. Future Athlon 64 Socket 939 chips will have 512K of level 2 cache as compared to the Athlon64 FX's full 1MB. This is actually not as bad as it might sound, since Athlon64 processors rely on cache less than equivalent Pentium 4 processors due to a more efficient core design. Reducing the size of the cache should also help AMD's manufacturing yields as the silicon core has shrunk in size from 193mm2 to 144mm2.

The enthusiasts out there will be happy to hear that Socket 939 Athlon64 processors still have access to lower multipliers. If you're really hardcore and have the money to spend, the Athlon64 FX line is completely multiplier unlocked!

There are a few other changes and upgrades to the Socket 939 platform as well. The HyperTransport link between the CPU and the motherboard has officially been upgraded from 800 MHz up to a full 1 GHz. This increases the bandwidth from 6.4GB/s to 8GB/s!

The extra speed and bandwidth should help get data between the CPU and the various other system components faster, increasing overall system performance.

Of course, with the introduction of Socket 939, Socket 940 is finished, at least in the consumer desktop market. If you're thinking about plugging a Socket 939 processor into a Socket 940 motherboard you're going to be disappointed. The processor will physically fit, but the two CPUs are not pin compatible. AMD will continue on with Socket 940 only for their workstation/server based Opteron processors. Socket 754 lives on of course, but it has quickly been relegated to the budget level platform, and AMD Sempron processor.