On 30 Mar 2012, Calvin Morrison spake thusly:

> Darrell, David,
>
> Number of cores tends to perform better -j4 for 4 cores. The +1 thing has
> been disputed numerous times :)

It also depends on hyperthreading, available memory, cache sizes, the
cache-friendliness of the compiler (GCC really isn't cache-friendly at
all) and a lot of other things.

On my hyperthreaded quad-core 2009-vintage Nehalem (256Kb K2 cache, 8Mb
shared L3 cache), I benchmarked GCC 4.5 as taking least time with -j 12
(for a sizeable parallelizable compilation). But it has a hardware RAID
array and 24Gb RAM, so it could easily keep up with those demands.

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