ATI's launch of the Radeon HD 4890 family has been blighted by a little confusion. The basic card, known as XT, ships with 850MHz/3,900MHz frequencies. Then there's the Radeon HD 4890 OC version, clocked in at 900MHz core and 3,900MHz memory, and we saw XFX's XXX interpretation of the card in our original look. Now, Sapphire brings it own reference-based OC version to the table, clocked in at 901MHz core 4,000MHz memory. The upshot is that it's a touch quicker than the 'regular' OC version and speedy enough to blur the performance gap that exists between it and a basic GeForce GTX 275. Sapphire, too, will be bringing custom-cooled Vapor-X and TOXIC models to retail, replete with even-faster clocks, and we expect to see them next month.