Many, many value RAM kits use Elpida.

I also see it in OEMS (HP, Dell, Acer, etc.) all the time.

You can try OCing them, but i wouldn't count on great luck.

OCZ is likely using different IC, or it's just the very best binned of all the crap.

Only value RAM ICs i've found to be pretty consistent for decent OCing is PSC.

I tried some ProMOS once (looked just like the stuff in the G.Skill Pis), & couldn't even do 1000.