Replies to post #3232 on Advanced Micro Devices Inc (AMD)

[fyodor]

kpf: Could you pls explain what that is? Or even better, what is the difference to the way AMD-CPUs run the cache?

For a more detailed explanation of cache associativity (or "way-ness"), please read e.g.:

http://www.arstechnica.com/paedia/c/caching/caching-5.html

The short-short version is that the higher the associativity, the more separate blocks of memory can be cached. The disadvantage is that the higher associativity results in a higher latency.

AMD's AthlonXP's L2 cache has a 16-way set associativity.

P4 and Banias are 8-way. Celeronized P4 is 4-way.

Two additional points:

- Intel uses a 4-way L1 (data) cache, whereas AMD's are all 2-way.
- Intel's L2 cache is "inclusive", meaning it contains all the data of the L1 cache as well. AMD's L2 is "exclusive", which (oddly enough) means it doesn't contain information found in the L1 cache.

-fyo