First off, superpi wont run on Itaniums
And superpi is only single threaded. So more cores does not equal better performance. Superpi is all about low latency and high clock speeds and memory bandwidth (yet, the A64 gets trampled by the Conroes) The 32MB L3 cache only helps up to a certain extent. It will benefit more in the longer super pi (32M) But you wont get very far trying to run Superpi.