In the past few years, looking at Intel CPUs, there has been a move from large size L2 cache to large size L3 cache.
A lot of this is due to having more cores on the CPU and wanting to share the cache between them (an L3 advantage).

But supposing I have a single threaded application and I want to compare the speed I get running it on 2 different CPUS that share the same clock speed :

1. a CPU with 6MB **L2** cache @3.1Ghz (e.g., Core 2 Duo E8500)
2. a CPU with 6MB **L3** cache @3.1Ghz (e.g., Core i5 2400)

Disregarding turbo boost effects and faster DDR factors,
*It seems the first (older) CPU should perform much faster (as it is closer to the core level), no ?*

Another question that interests me, In old times, back in the first days of L2 cache in CPUs I seem to recall that L2 cache is accessed at half the CPU clock speed, *is that still true today ? and what about L3 speed ?*