Inside the Athlon XP 3200+

The Chip

The most significant development of today’s launch is the new 400MHz front side bus. In transitioning to a faster bus, AMD has enabled a bandwidth increase of roughly 16 percent. Performance doesn’t scale according to that figure, but the higher bandwidth number coupled with the use of low-latency DDR memory should allow for a moderate boost all around.

Because of the newly added bus speed, AMD has had to revamp its multiplier settings that determine a processor’s operating frequency. The Athlon XP 3000+ runs at 2.17GHz, which is derived from a 166MHz bus multiplied by 13. The new 3200+ operates at a round 2.2GHz (200MHz * 11). Incidentally, the 3200+ is about 30MHz faster than its predecessor. The rest of the chip’s attributes are unchanged. It is still based on the ‘Barton’ core, with 128KB of L1 and 512KB of L2 cache. AMD’s Dresden, Germany-based Fab30 handles production of the chip on its .13-micron process. Apparently, the process still has some life in it, as the 3200+ requires the same 1.65V as the 3000+ before it. The processor does dissipate a bit more heat, though. Its maximum thermal power is 76.8W compared to 74.3 for the 3000+.

Platform Support

AMD touts the fact that the Athlon is still running on the Socket A interface, but it should be noted that platform support is fairly limited for processors utilizing a 400MHz front side bus. In fact, unless you’ve managed to get your nForce2 board running stably at 400MHz, you’ll likely need a new motherboard. Such is the life of an early adopter, unfortunately.

On the bright side, the infrastructure necessary to support the 3200+ is already in place. SiS’ 748 chipset should be available shortly, working properly with a 400MHz bus and a single channel of DDR400 memory. It also sports SiS’ proprietary MuTIOL 1G technology that links the 748 North Bridge to the 963L South Bridge with a 1GB per second interconnect. Unfortunately, SiS’ 964 South Bridge (with Serial ATA) isn’t quite ready, so motherboard manufacturers will have to continue incorporating third-party controllers for that particular feature.

VIA’s entry to the 400MHz will be a bit later. It’s been a while since its KT400A chipset sampled, yet we still haven’t seen widespread adoption of that product, and it is a 333MHz platform. VIA is reportedly working on its KT600 chipset, which will support the new bus but probably won’t be out before this summer. If VIA encounters further delays, it risks missing an important window of opportunity before Athlon 64 is readied later this year.

Not one to be left out, NVIDIA is unveiling two new chipsets concurrently with the 3200+ launch. The first, nForce2 400, is a single-channel solution that only works with NVIDIA’s value-oriented MCP. The second has been dubbed nForce2 Ultra 400. It sports two channels of DDR400 memory and accepts either the MCP or the higher-end MCP-T (the MCP-T supporting FireWire, dual Ethernet MACs, and Soundstorm audio). Both the nForce2 400 and nForce2 Ultra 400 are System Platform Processors, meaning none of the 400MHz platforms will include integrated graphics. Instead, NVIDIA expects that the enthusiasts interested in a flagship processor like the Athlon XP 3200+ would prefer a discrete graphics solution. NVIDIA claims that motherboards based on nForce2 Ultra 400 will be available immediately. Considering that our tests were run on an ASUS A7N8X Deluxe Revision 2.0, we’d tend to believe NVIDIA.