Memory performance
Our customary synthetic memory benchmarks will start us off, and we can see how the A64 3400+'s single channel of DDR400 memory compares to the dual-channel solutions so common nowadays.

The results show a clear difference between the 3400+ and the dual-channel solutions. These synthetic benchmark scores may not translate directly into real-world performance, but they may be a primary reason for the existence of the dual-channel Athlon 64 FX.

The only real difference between the Athlon 64 3400+ and the A64 FX-51 is the number of memory channels, as Linpack demonstrates. The two processors perform identically until matrix sizes become large enough for main memory to matter. Note, though, how the A64 3400+'s on-die memory controller allows it to achieve much higher throughput than the Athlon XP 3200+. In fact, the 3400+ just barely falls behind the Pentium 4 3.2GHz, and then only at the largest matrix sizes.

Memory latency is the 3400+'s real strength. The dual-channel Athlon 64 FX requires registered DIMMs, and those add a cycle of latency to memory accesses. As a result, the 3400+ beats everything in our memory latency test. Notice, especially, the massive latency difference between the Athlon XP 3200+ and the Athlon 64 3400+, which run at the same 2.2GHz clock speed. This is one of the main reasons why AMD is now able to run with the Pentium 4 so well.

Let's dwell on this point with some 3D graphs..