As for the structure of cache memory, the L2 cache of the Athlon 64 (just like the L2 cache of Athlon XP) features 16 associativity fields and 64-Byte long lines.

L2 cache of Athlon 64 is built like the L2 cache
of the current Athlon XP
Speaking about the support of different technologies, we should resort to the results obtained with the help of SiSoft Sandra 2003 benchmark:

3DNow!, x86-64 and SSE2 are all here
As we have expected, the CPU supports old instructions sets, like: MMX, 3DNow!, and SSE, as well as SSE2 and x86-64, which are completely new for AMD processors. Also note that the CPU features a built-in thermal diode. Hopefully, Athlon 64 is a hard nut to cook. Also AMD has finally listened to users’ complaints and hid the fragile CPU die under a copper lid with nickel-plated surface.
The CPU we tested was built with the B0 core revision. It is a much newer core than those used in the very first samples working at 800MHz and 1.2GHz core frequency. AMD redesigned this core to increase the clock frequencies and improved the embedded memory controller a little bit. As a result, our processor supported not only DDR266/DDR333 SDRAM, but also DDR400 SDRAM. However, unlike the server Opteron CPU, Athlon 64 will have a single-channel memory controller that is why the maximum memory bandwidth of the Athlon 64 based systems will make 3.2GB/sec.
As for HyperTransport bus, connecting Athlon 64 with the mainboard chipset, our CPU featured one 16bit bus working at 800MHz, which provided the bandwidth of 3.2GB/sec in each direction. However, we doubt that Athlon 64 will really need such a high-performance bus, because unlike other CPUs, it will not transfer any data to/from the system memory. Anyway, extra bandwidth has never been a drawback.
Summing up everything we have just said, I composed the following table listing the major features of contemporary desktop CPUs:
CPU | Athlon 64 | Athlon XP | Pentium 4 |
Core | ClawHammer | Barton | Northwood |
Production schedule | Fall 2003 | Early 2003 | Early 2002 |
Frequencies | 1.6GHz+ | 1.83-2.2GHz | 1.6-3.2GHz |
Production technology | 0.13micron SOI | 0.13micron | 0.13micron |
Platform | Socket 754 | Socket A | Socket 478 |
Bus frequency | 800MHz | 333/400MHz | 400/533/800MHz |
L1 cache for data | 64KB | 64KB | 8KB |
L1 cache for instructions | 64KB | 64KB | 12KB |
L2 cache | 1024KB | 512KB | 512KB |
L2 cache frequency | Full core frequency | Full core frequency | Full core frequency |
Additional instructions sets | |||
MMX | + | + | + |
3DNow! | + | + | - |
SSE | + | + | + |
SSE2 | + | - | + |
x86-64 | + | - | - |



