in that case am not sure why you had the need to upgrade from a 8800 gts in the first place..unless u play on 2560 resolution on a 30 inch monitor, even then WoW is so easy on graphics card i think the 8800 gts would still have suffice
edit. i see you have a 22 inch monitor, honestly I would'nt have upgraded to a 4890 for Wow on that resolution