4x 288w on full load equals 1152w plus your other hardware need some power too... New PSU required
4gb ram is too low for 4 cards...Upgrade to 8
Do this first and then consider tweaking your settings again
I thought about that too. I unplugged two cards so 1050W can easily handle the rest two. still no improvement on hashrate.
would memory matter that much? I saw there are still around 2GB left all the time.