The New Athlon Processor: AMD Is Finally Overtaking Intel

The Second Level Cache

Let's move from outside to inside. The second level cache of the Athlon models we've got in our lab is 512 kB, running at 1/2 the core clock speed, just the same as Pentium III. However, Athlon was designed with a very flexible second level cache in mind. The L2-cache size can range from 0.5 to 8 MB, the L2-speed can range from a ratio of 1/3, 1/2, 1/1.5 to 1/1 L2-cache clock / processor core clock. This opens up a very wide field of possibilities for segmentation of Athlon. The low cost versions could get small and slow caches, workstation and especially server version could be equipped with up to 8 MB of L2-cache running at core clock.

In my eyes the L2-cache is also one of Athlon's weaknesses. Due to the fact that Athlon's L2-cache is 'external', meaning 'not on the die', limits it to the SlotA-SEC-package. Intel is on the way to leave Slot1 and the single edge cartridge, simply because it's more expensive and less practical than a socket. Intel is only able to move away from Slot1 because the upcoming and delayed 'Coppermine' will have its 256 kB L2-cache integrated on the processor-die. AMD will have to go in this direction (and thus to .18 µ-process) very soon too, if it wants to stay competitive.

Anyway, the L2-cache of Athlon is a very flexible thing and as long as Pentium III is also using external L2-cache, there's no reason to complain.