Hardware Reference
In-Depth Information
The Athlon 64 and 64 FX are available in four socket versions, the core features of which
are detailed in
Table 3.22
. Note that Socket 940 supports only slower and more expensive
registered DIMMs. Because of this, you should avoid Socket 940 processors or mother-
boards.
Table 3.22 AMD Athlon 64 and 64 FX Socket and Memory Types
The Athlon 64 essentially comes in three versions: a Socket 754 version that has only
a single-channel memory bus, an improved Socket 939 version that has a dual-channel
memory bus, and an even better Socket AM2 version that has a dual-channel DDR2 bus.
The Athlon 64 FX is also available in three versions: a Socket 940 version that uses ex-
pensive (and slower) registered memory, an improved Socket 939 version that uses un-
buffered memory, and an updated version that uses dual-channel DDR2. The Socket 939
versions of the Athlon 64 and 64 FX are essentially the same chip, differing only in the
amount of L2 cache included. For example, the Athlon 64 3800+ and Athlon 64 FX-53
both run at 2.4GHz and run dual-channel memory. The only difference is that the 3800+
has only 512KB of L2 cache, whereas the FX-53 has 1MB of L2 cache. Because the 64
and 64 FX chips are essentially the same, you need to read the fine print to determine the
minor differences in configuration.
The Athlon 64 FX can draw up to 104W or more of power, which is high but still some-
what less than the more power-hungry Pentium 4 processors. As with the Pentium 4,
motherboards for the Athlon 64 and 64 FX generally require the ATX12V connector to
provide adequate 12V power to run the processor voltage regulator module.
The initial version of the Athlon 64 is built on a 0.13-micron (130-nanometer) process.
Subsequent versions use either a 0.09-micron (90nm) or a .065-micron (65nm) process.
