The technology
The architecture
As is clear by the nomenclature, the Radeon HD 5570 is to fill the gap between the HD 5450 (£40) and HD 5670 (£70). The architecture, then, will fall somewhere inbetween the two.
Click to enlarge
Has AMD made a mistake and substituted the HD 5670's architecture in the above picture? The answer is no, because the 'top-end' of the HD 5570 is exactly the same as the 5670's. The GPU has the same 400 stream processors, 20 texture-units, 8 ROPs, and a 128-bit memory interface.
By the use of the words 'up to', it is reasonable to assume that we will see other 5500-series cards with a SIMD engine disabled and four texture-units inactive. The reason for doing so will be down to GPUs that don't quite make the HD 5570 grade and are then branded lower-specified cards - HD 5550, for example.
So how is it different to the HD 5670, then?
Take most of HD 5670 and sprinkle a little HD 5450
| GPU | Process | Transistors | Stream Processors | Texture
units |
ROPs |
Memory
width (bits) |
Memory type | Max board power (watts) | Idle board power (watts) | Etail price (US dollars) |
|---|---|---|---|---|---|---|---|---|---|---|
| Radeon HD 5870 | 40nm | 2,080m | 1,600 | 80 | 32 | 256 | GDDR5 | 188 | 27 | 399 |
| Radeon HD 5770 | 40nm | 1,040m | 800 |
40 | 16 | 128 | GDDR5 | 108 | 18 | 165 |
| Radeon HD 5670 | 40nm | 627m |
400 | 20 | 8 | 128 | GDDR5 | 61 | 13 | 95 |
| Radeon HD 5570 |
40nm | 627m | 400 | 20 | 8 | 128 | GDDR3 | 42.7 | 9.69 | 75-85 |
| Radeon HD 5450 |
40nm |
292m |
80 |
8 |
4 | 64 |
DDR2/GDDR3 |
19.1 |
6.4 |
49-59 |
| Radeon HD 4670 |
55nm | 514m | 320 | 32 | 8 | 128 | GDDR3/GDDR4 | 59 | 20? | 75 (GDDR3, now) |
The HD 5570 GPU contains the same number of transistors and is the same size - 110mm² - as the HD 5670's. The main high-level difference is that the board is kitted out with cheaper GDDR3 memory, compared with the GDDR5 on the faster GPU. This translates to considerably lower memory-bandwidth and a somewhat lopsided design.
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The other major difference is with respect to the GPU's core speed, which drops from 775MHz on HD 5670 to 650MHz on the HD 5570. A reduction in operating frequencies helps reduce board power from 61W/13W (HD 5670) to 42.7W/9.69W on this model, and we should see passively-cooled models being made available sooner rather than later.
Pragmatically, Radeon HD 5570 1,024MB will start from £60, putting it just above the NVIDIA's GeForce GT 220 and, looking back, AMD's very own Radeon HD 4670. Comparing against the previous generation AMD card on a price-to-price basis, the decision to reduce the ratio of stream processors to texture-units (20:1 for HD 5570 and 10:1 for HD 4670) may mean the newer GPU trips up in scenarios where texture fillrate is important.
