> You really only need dirty_ratio/bytes and dirty_background_ratio/bytes set to something lower than default.

The vm.swappiness=1 was very necessary for me as well, and made as much difference as the dirties you'd mentioned.

I usually run Linus' master kernels (as I look for regressions in certain subsystems) and I know there's been some recent changes to the MM subsystem so this may explain some of the necessity for me.