TrustedReviews have looked at the Sapphire TOXIC X1950 XT-X

Standard speeds for the X1950XT-X are 650MHz core clock and 1GHz (2GHz effective) memory clock. This particular card has a higher core clock than standard, coming in at 695MHz, though memory speeds stay as standard. This is a fairly decent improvement, considering the X1950XT-X isn't known to be a huge overclocker, and will hopefully provide a noticeable boost in performance.

Sapphire TOXIC X1950 XT-X Review