Socket-939 at the ready!
We'll start off by examining the key features of the new CPUs.| CPU | AMD Athlon 64 FX-53 (S939) | AMD Athlon 64 Model 3800+ (S939) | AMD Athlon 64 FX-53 (S940) | AMD Athlon 64 Model 3400+ (S754) |
| Clock speed | 2.4GHz | 2.4GHz | 2.4GHz | 2.2GHz |
| L1 cache | 128kb | 128kb | 128kb | 128kb |
| L2 cache | 1024kb | 512kb | 1024kb | 1024kb |
| Memory controllers | 2 | 2 | 2 | 1 |
| Memory bandwidth | 6.4GB/s | 6.4GB/s | 6.4GB/s | 3.2GB/s |
| Memory support | DDR400 dual-channel | DDR400 dual-channel | DDR400 dual channel (registered) | DDR400 dual-channel |
| FSB | 2.4GHz (core speed) | 2.4GHz (core speed) | 2.4GHz (core speed) | 2.2GHz (core speed) |
| Transistor count | 105.9m | 105.9m | 105.9m | 105.9m |
| OS support | 32/64-bit | 32/64-bit | 32/64-bit | 32/64-bit |
| Form factor | Socket-939 | Socket-939 | Socket-940 | Socket-754 |
| Operating voltage | ~1.5v | ~1.5v | ~1.5v | ~1.5v |
| Heat output | 103w? | 103w? | 89w | 69w |
* There's also Model 3700+ (socket-754 - 2.4GHz - 1MB L2 cache) and Model 3500+ (socket-939 - 2.2GHz - 512kb L2 cache) released today.
Previously, dual memory channel support was only available with the FX-series of CPUs. One also had to factor in the use of registered memory as regular unbuffered RAM, which is what the vast majority of home PCs use, simply didn't work. FXs were, in effect, rebadged server-class Opterons. Now AMD's extended the FX's dual-channel integrated memory controller to CPUs that can, as you will have guessed, use regular memory. That's a huge bonus to enthusiasts wishing to force up the driven clock to, say, 250MHz and still keep synchronous memory support. Unbuffered RAM is also available with tighter latencies than registered modules, so the S939 FX-53 should be the pick if absolute performance is high on your priorities' list.
There's now four AMD processors that run at 2.4GHz. We've already reviewed the S940 version over here and found it to be a potent performer. The S939 version, running at the same speed and also sporting 1MB of L2 cache, is also confusingly called the FX-53. So we have one FX-53 that has 940 pins and requires registered memory in order to function, and another with a single pin less that doesn't. Note that both FX-53s require different sockets and platforms.
The third 2.4GHz AMD Athlon 64 is the Model 3800+. It's also a S939 chip that differs from the FX-53 (S939) by only having 512kb of L2 cache. Our Model 3000+ (S754), which is another 512kb L2 cache-equipped CPU, benchmarked in very close proximity to the 1MB L2 cache Model 3200+. That suggests the 3800+ will be a decent performer. Then to confuse you even more, there's a S754 2.4GHz CPU that goes by the nomenclature Model 3700+
Other than supporting unbuffered RAM and change to a different socket that will lead to both VIA and NVIDIA launching compliant chipsets, there's nothing new, silicon-wise, that AMD's bringing to the table. That's not bad thing, really, as Athlon 64s are damn fast at default or near-default speeds. Talking about AMD's premier CPUS generally, the new Enhanced Virus Protection is a nice touch. Parts of system memory are set aside and configured such that code cannot be executed, simply read from and written to. Virus of this kind are then contained and eventually flushed from system memory. Note that Windows XP Service Pack 2 will be required for this feature to work.
Vigilance and careful research is key to purcashing upcoming Athlon 64s. They span three sockets and there's multiple CPUs at identical speeds.
