if gcc uses more memory than physically available it spends a _very_ long time swapping
Swapping, what's that? Here's $20, go buy a gigabyte.
Now, having said that, we do believe that it would make for interesting research to try less memory intensive algorithms, or to rearrange code so that the working set is reduced to help boost cache hits. Currently gcc takes a cache miss every 20 instructions, or some ungodly number, and that really saps performance.
This is, generally speaking, just lots of hard work.
Good luck, let us know how it turns out.
