Noticable lag with Heal and Spot removal in 8.3. Graphics?

I'm noticing considerable lag in 8.3 when drawing masks for a heal layer and when making spot removals (Spot more so than Dust). Masks can take quite a few seconds to appear.

Is anyone else noticing this?

Could it be my graphics card? I'm using a Quadro FX1700. All drivers are fully up to date.

If not, what might it be?

Anything in Preferences I should be looking at?

Thanks.

D.

Ps. For what it's worth, on the recommendation of Support, I have also just deleted the user.config file from my User/App Data folder. It fixed the problem I was having with the Color Editor.