L3 caché it's very important, especially in the PPC era where the CPU speed was increased a lot more than system bus speed. Even true that everybody claims that 2 MB of L3 is better than only 1 MB ... but how much?
I have changed my 1.5 Ghz MDD cpu with
1MB of L3 cache by a 1.5 Ghz cpu with
2MB of L3 cache from a xServe ( both CPUs overclocked at 1.5 Ghz) and make some test before and after the change. So being exactly the same machine, if some differences appear, the cause will be the amount of L3 caché.
MacBench 3 only shows a
10% of speed increase on hardisk related test.
Cinebench 2003 show a suppressive
50% of speed increase on the rendering test ( something went wrong in this test I think ) , and a
10 % of speed increase in the Shading test.
The most important test was the
video encoding test, because it uses a lot of CPU and memory bandwidth. I had taken the
average of encoding 4 times the same video before and after the CPU change and comparing the average encoding speed in both cases the result was a
5% faster using the 2MB L3 CPU.