Graphics cards based on the RADEON X1800 XT clock the chip at 625MHz and the memory on 1500MHz.RADEON X1800- and RADEON X1300-series graphics cards are currently available from retailers and e-tailers including CDW, CompUSA, Fry???s, Monarch Computers, NewEgg, Tiger Direct and RADEON X1600-series is expected to ship later in the fall, ATI explained.