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AMD's Athlon XP 3200+ processor

The 400MHz bus stops here

THIS IS a simple one. AMD is introducing a new Athlon XP variant today dubbed the 3200+. This processor runs at 2.2GHz on a 400MHz front-side bus, which means the CPU is 33MHz faster than its predecessor, while the bus is 66MHz faster.

Beyond that, there's not a lot new to report. So, after spending untold hours benchmarking a wide range of comparative systems against this new AMD processor, I am currently ingesting a carefully tailored cocktail of stimulants and depressants in order to summarize my results with sparkling wit and rapier prose.

Or something like that.

Anyhow, this new processor from AMD should address some concerns we've had about the Athlon XP platform's ability to keep up with the Pentium 4 in memory and bandwidth-intensive applications. The release is especially timely in light of Intel's recent introduction of a new Pentium 4 3.0GHz chip with an 800MHz front-side bus. Although the Athlon XP's effective bus clock speed is half that of the quad-pumped bus on the Pentium 4, both processors' nominal bus speeds are 200MHz. The Pentium 4 tends to do an awful lot of very aggressive prefetching of data from memory into on-chip cache, so the P4 especially likes a fast bus and fast memory. The Athlon XP also has prefetch logic, but we've found it to perform relatively well in real-world benchmarks even when it has a pronounced set of disadvantages in clock speed, bus speed, and total memory throughput.

In other words, the Athlon's move to a 400MHz bus may put it right back into the game against the screaming fast Pentium 4 3.0GHz with an 800MHz bus. Of course, we have a full set of benchmarks results, so you can see whether or not this puppy delivers.

Beyond the slightly higher clock speed and the faster bus, the Athlon XP 3200+ isn't much different from previous spins of the "Barton" core. The chip has 512K of L2 cache, and is built using AMD's 0.13-micron copper fab process.

The Athlon XP 3200+ processor

The biggest news beyond this new CPU with a faster bus is, of course, in chipsets.

NVIDIA's new nForce2 flavors
With support for a 400MHz bus on the Athlon XP comes a pair of new chipset products from NVIDIA under the nForce2 umbrella, the nForce2 Ultra 400 and the nForce2 400. Near as I can tell, the nForce2 Ultra 400 is the familiar nForce2 chipset with dual-channel DDR400 and official support for a 400MHz bus. If I'm right about that, I suppose the Asus A7N8X Deluxe 2.0 motherboard we're using to test the Athlon XP 3200+ today is based on the nForce2 Ultra 400 chipset. Little did I know.

The nForce2 400, meanwhile, is a little more novel. The nForce2 400 has support for only one channel of DDR400 memory, and it doesn't support the MCP-T south bridge chip, so it won't have features like AC-3 audio, Firewire, or a 3Com NIC. The nForce2 400's obvious mission in life is to take on VIA's KT400A head to head, while establishing NVIDIA's nForce2 Ultra 400 as a premium product.

Clever, no?

VIA's answer: KT600
VIA has its own chipset refresh in the works with 400MHz bus support, and they've gained tactical numerical superiority by calling their chipset the KT600. The KT600 isn't a dual-channel DDR solution, but a second channel of memory isn't usually all that helpful on the Athlon XP platform anyhow. The KT600 is different from the KT400A in two basic ways: it has a slightly optimized memory controller, and official support for a 400MHz front-side bus. Beyond that, the KT600 is essentially the same thing as the KT400A.

VIA says KT600 motherboards should begin arriving within weeks. NVIDIA's nForce2 400 series is shipping now, so NVIDIA has a bit of a head start here. Given NVIDIA's impressive success with the nForce2 and VIA's tenacity, the Athlon XP 3200+ should be set for quality core-logic chipsets. The tough question may be which one to choose.

We'll revisit this little chipset spat once a KT600 board arrives in Damage Labs, which should be fairly soon. For now, let's get on to the CPU benchmarks.