Noatime is actually pretty awesome at relieving disk i/o issues. The main kernel devs are actively discussing making this a default part of linux as well.
I used to be a sr admin for one of the bigger hosting ops and we rolled this out across all servers and saw a nice (not *omg epic*) but nice decrease in i/o problems.
However it should be noted that if you're currently on a single disk setup, slow drivers/etc, your biggest and best gains are going to be seen by going with a newer raid card and faster drives. noatime is really only good for a bit of an improvement.