Sapphire Radeon HD 4890 XT 1,024MB
Here's a card that you'll be seeing a lot more of soon: the Radeon HD 4890 XT 1,024MB. Remember, the RV790's released in two flavours - the stock-clocked XT (850MHz/3,900MHz) and overclocked OC (900MHz/3,900MHz+), costing at least £200 and £225 on launch-day, respectively.
On first glance the card looks suspiciously like a Radeon HD 4870 - no surprises there - and the PCB is the same size, measuring 240mm x 110mm x 34mm (WxHxD). Further, it matches the HD 4870 in the fatty stakes, tipping the scales at 825g or so.
Indeed, there's very, very little outward differences between the two, and click here for a picture of the HD 4870. Feel free to play the perennial favourite spot-the-difference game.
The magic, if you will, is under the heatsink/fan, which, on this model at least, is a touch louder than HD 4870 when placed under load. The GPU throttles down to 240MHz core when idling, but the card still has three distinct power-states - although ATI claims a 30W reduction in idle power.
The 1,024MB memory chips - eight in total - are located on the topside. Just like the GPU, the speed has been increased, from 3,600MHz to 3,900MHz - an 8.33 per cent rise. It's still GDDR5 memory, of course, and we've already seen a slew of partner-overclocked HD 4870s with matching memory speeds.
The double-height cooler's a proven design now.
Higher-than Radeon HD 4870 clock-speeds means that voltages have been turned up a notch. The Radeon HD 4890 XT 1,024MB, also based on the same 55nm process, is reckoned to pull around 190W under load - some 30W higher than HD 4870.
Rear-mounted outputs remain the same. Partners will add their own slant to the connections when custom cards become available, so expect to see HDMI- and DisplayPort-equipped models appear in the next month.
Summary
A generic design that could easily be mistaken for a Radeon HD 4870, Sapphire's Radeon HD 4890 XT 1,024MB should be available today for around £199, including VAT, making it some £30-£40 more-expensive than a Radeon HD 4870 1,024MB. What more do you get? A 13.3 per cent increase in core/shader speeds and 8.3 per cent on the GDDR5 memory.
