It hardly feels like it but it's actually been nine months since AMD/ATI released its last single-chip high-end graphics card, the HD 4870. Now that may not be a great length of time in most walks of life but in the computer industry where we quite often see new releases every six months, that's quite a stretch. Nevertheless, ATI has today launched the HD 4870s successor, the single-chip HD 4890.
Available immediately and, in the case of the XFX card we're looking at, priced at £229.99, it's about the same as the HD4870 was at launch and £60 more expensive than the HD4870 1GB is currently. This makes its nearest competitor from nVidia, the GTX 260 and will immediately alert you to the fact this is not a card meant to compete at the bleeding-edge in terms of performance. Still £200 can get you a heck of a lot of bang for your buck so let's see how the HD 4890 holds up.
The card itself is outwardly very similar to the HD 4870 with the same 9.5in PCB length, identical dual slot cooler design, and same duo of extra power connections on its front edge. The video output configuration is also identical with two dual-link DVI sockets and a multi-format analogue output that natively supports S-Video but also outputs component and composite with the help of dongles. Meanwhile, the top edge of the PCB is home to the usual pair of Crossfire connectors.
Casting an eye over the specification of the actual graphics chip, reveals that the card looks pretty similar internally, as well. The HD 4890 still features 800 stream processors, 40 texture units, and 16 ROPs, communicating across a 256-bit wide interface to1GB of GDDR5 memory. However, this new chip has been completely reworked to enable it to run at higher clock speeds. Specifically, a ring of decoupling capacitors has been added round the whole chip to reduce signal noise and the relative timings of all the components have been tweaked.
The result isn't particularly dramatic with just a 100MHz (13 per cent) increase of core clock speed but along with faster memory it should result in a noticeable boost in performance. Consequently the transistor count has gone up slightly, from 956 million to 959 million, but the difference is likely to have a negligible impact on production, and thus final board, costs.
ATI has also focussed on making the new card less power hungry when idling. We couldn't get any specific details as to what measures had been taken to achieve this but ATI quotes that idle power has dropped from 90W on the HD 4870 to 60W on the HD 4890. Unfortunately this isn't something that's carried over to the card running at full pelt where the HD 4890 now consumes 190W, up from 160W on the HD 4870.
With so little changes to talk about we might as well get right onto testing.