Radeon HD 4890 XT and OC - how they compare
Le Roi est mort, vive le RoiToday, the single-GPU Radeon king, HD 4870, is being supplanted by another card, the Radeon HD 4890 1,024MB. The nomenclature indicates that it's of the same generation and family as the '70, which it is, and it can be thought of, quite accurately, as a faster-clocked Radeon HD 4870.
We'd normally be moved to write volumes on a 'new' GPU, but the differences between Radeon HD 4870 and HD 4890 are few and far between. Let's replace verboseness with a table:
| Graphics cards | ATI Radeon HD 4870 | ATI Radeon HD 4890 XT | ATI Radeon HD 4890 Overclocked |
|---|---|---|---|
| Codename |
RV770 | RV790 | RV790 |
| Process (nm) |
55 | 55 | 55 |
| Transistors (mn) |
~956 | ~959 | ~959 |
| GPU clock (MHz) |
750 | 850 | 900 |
| Shader clock (MHz) | 750 | 850 | 900 |
| Memory clock (MHz) | 3,600 |
3,900 | 3,900 |
| Memory sizes (MB) |
512, 1,024, 2,048 |
1,024 | 1,024 |
| Memory bus width (bits) |
256 | 256 | 256 |
| Shader units | 800 | 800 | 800 |
| ROPs | 16 | 16 | 16 |
| Idle board power (watts) | 90 | 60 | 60 |
| Max board power (watts) | 160 | 190 | 190 |
| Etail price (£) | £150 (512MB), £170 (1,024MB) | £199+ | £225+ |
Analysis
There will actually be two new Radeon GPUs released today, differentiated on core speed and nothing else. A look at the vital statistics reveals that the Radeon HD 4890 XT - that's the 'regular' version, folks - will ship with an 850MHz core/shader speed and GDDR5 memory operating at 3,900MHz. Further, it will be equipped with a 1,024MB frame-buffer alone; there's no other option at launch. We've already seen a slew of partner-overclocked Radeon HD 4870 1GBs, usually hitting 800MHz core and 4,000MHz RAM, so the introduction of RV790 will render them moot unless pricing drops massively.
