If there is one law that AMD seems to have fallen victim to, it would be that of diminishing returns. In the processor world, this amounts to continually increasing core speeds without any major changes to the CPU core or the platform base. As processor speeds rise, the overall impact is muted due to the static platform and CPU formats. The Athlon XP 2600+ illustrated this quite well, as it was a nice speed jump over previous models, but still ran on the same 266 MHz bus as its predecessors. The addition of 333 MHz DDR memory has helped a bit, but there was still the issue of asynchronous CPU/memory bus speeds, with the CPU side being the slower of the two.
This didn't compare well to Intel and their incredible core and platform upgrades to the Pentium 4 line. The Pentium 4 Northwood core doubled the L2 cache from 256K to a full 512K, and the transition to the 533 MHz front-side bus also brought in some inherent performance increases. With 333 MHz DDR being the standard configuration, and DDR400 only starting to make in impact, Intel platforms are also running on an asynchronous CPU/memory bus, but overall speeds are higher and the performance ratio was still in favor of Intel.
AMD has now countered this Intel strategy with their Athlon XP 2700+ and 2800+ processors, which not only up the core speed ante but bring with them a faster 333 MHz front-side bus. Moving to a faster bus speed is far more important than simply raising the core to ever-higher levels, especially now that both the CPU and memory bus speeds are equally matched at 333 MHz. This should not only provide for greater memory performance, but allow the Athlon XP additional performance headroom for future revisions.
In this review, we'll be checking out the Athlon XP 2700+, which is one of the new AMD processors announced today. Since this CPU heralds the arrival of the 333 MHz FSB and looks to take on Intel at the high-end of the processor market, the majority of our examination will be determining performance levels, and comparing those to competing Intel and AMD models.
The Athlon XP 2600+ was a much-needed core revision that not only helped close the performance gap with the Pentium 4, but also provided a great deal more clock speed headroom than we had initially forecast after the Athlon XP 2200+ review. The Athlon XP 2800+ and 2700+ make use of these core enhancements, but also increase the front-side bus to 333 MHz. In a nutshell, that's the gist of the announcement, as the rest of the physical specs remain unchanged. The Athlon XP 2800+ and 2700+ are built on a 0.13 micron copper process, run on 1.65V, feature 128K of L1 and 256K of L2 cache, and can utilize many existing Socket A motherboards.
This last point deserves addressing, as the 333 MHz FSB of the Athlon XP 2700+ and 2800+ requires a motherboard that fully supports, at standard 66 MHz AGP and 33 MHz PCI, the 333 MHz bus speed. In terms of chipset support, this amounts to the VIA KT333 & KT400, NVIDIA nForce2 and SiS 746, though just because the chipset supports the 333 MHz FSB feature does not mean the individual manufacturers implemented it. We have reviewed several motherboards using the above-mentioned chipsets that when set to 333 MHz, do not have the necessary dividers for standard AGP and PCI speeds. AMD will be posting compatible motherboards once the testing is complete, so confirm support before making any upgrade plans.
