Getting lag/low fps and tearing on 4870X2

[Boyiee]

So lately on WoW I've been getting a bit of lag with a drop in FPS randomly, I run at high settings on a HD4870X2 card with a strong enough computer to run this game at full settings. Crysis and fallout etc all run fine at high settings.

When it gets annoying, I turn vertical sync on and it stops, but I really don't like having to do that. My addons tell me at some points ill hit 140-160fps and even in hardcore raids with effects and shit I still have 60-90 running smoothly. There was a point in time at which shadows caused some flashing, but it hasnt happened in a while.

But just flying around lately and doing typical things like quests on an alt with like noone around me Ive seen big dips in fps and it's really frustrating. The system is not overclocked, however I did recently add a 2nd monitor that is also 1920x1200 and I'm sure that has to do with some of it, but I really don't think this should be happening even with that.

Should I try OCing the card/system? I was thinking of reformatting one of my drives, I suppose that could help... the computer is only as old as december and it was of course built at december specs but it shouldn't need any upgrades.

Case runs cool, have a 120 Zalman on the cpu, right now card is at 45C with 75% fan speed to keep it cool. The ram has its own fans, the case is a Antec900 lots of airflow. There is a LOT of wiring that could cause a loss of airflow but I can't do anything about it unless I change to a bigger tower, but even with the obstacles the case has so many fans I don't think it would be too hot.

E8500
HD4870X2 (not two of them, the X2 card)
4gb ram
Vista
big enough PSU
rampage mobo
games are on a 10k rpm drive.

[Cephius]

There's no way your system should be incapable of running WoW smoothly. Obviously you'll get the occasional lag in Wintergrasp or Dalaran, but it should be fine without overclocking. I'd try disabling all your add-ons and then seeing if the lag/tearing goes away.

If it does, you know it's an add-on causing your problems and not your system.

[Tythera]

I read that a number of people got a big boost in some games from going to the 9.8 catalysts, have you tried those? Maybe they'll also fix the other issues if it's not the add-ons.

[Kurp]

Why are you against using vertical sync if it fixes the problem?