I built Chromium from source the other day on my machine with 4GB of RAM. It hit swap while linking. Also, I'm running a 64-bit Linux distro. A 32-bit system I tried could not link Chromium at all.
All of this is documented in the Chromium wiki, of course. But the point is, 4GB memory is their minimum requirement, and insufficient for doing a lot of work on a project like Chromium.
Damn, I thought needing something like 3GB to compile PyPy on 64-bit put us in some class on unreasonable usage, interesting to see that it's apparently not so crazy for large projects.
I have 8 servers running distcc for my compilation chores, however none of them has more than 8 GB of RAM. IIRC I had no problem compiling firefox with my puny workstation. Chrome is as nasty as OOo :)
All of this is documented in the Chromium wiki, of course. But the point is, 4GB memory is their minimum requirement, and insufficient for doing a lot of work on a project like Chromium.