Radeon HD 7730 explored
New graphics processing units (GPUs) tend to be announced with great fanfare. AMD and Nvidia's marketing machines are usually running at full chat when there's a new launch, helping their partners to promote the latest-and-greatest technology.
The regular brouhaha has been curiously missing from a desktop AMD GPU officially released three months ago. Known as the Radeon HD 7730 and codenamed Cape Verde LE, this £60 GPU has been surreptitiously slipped into the catalogues of a few leading add-in board (AIB) partners. We'll take a look at a Sapphire card once we've unearthed the provenance of the HD 7730.
| GPU | Radeon HD 7750 |
Radeon HD 7730 |
Radeon HD (5)6670 |
|---|---|---|---|
| Codename | Cape Verde Pro | Cape Verde LE | Juniper XT |
| DX API | 11.1 | 11.1 | 11 |
| Architecture | GCN | GCN | VLIW5 |
| Process | 28nm | 28nm | 40nm |
| Transistors | 1.5bn | 1.5bn | 716mn |
| Die Size | 123mm² | 123mm² | 118mm² |
| Processors | 512 | 384 | 480 |
| Compute units | 8 | 6 | 10 |
| Texture Units | 32 | 24 | 24 |
| ROP Units | 16 | 16 | 8 |
| GPU Clock (MHz) | 800 | 800 | 800 |
| Shader Clock (MHz) | 800 | 800 | 800 |
| GFLOPS | 819 | 614 | 768 |
| Memory Clock (MHz) | 4,500 | 4,500 | 4,000 |
| Memory Bus (bits) | 128 | 128 | 128 |
| Max bandwidth (GB/s) | 72 | 72 | 64 |
| Power Connectors | None | None | None |
| TDP (watts) | 55 | 47 | 66 |
| GFLOPS per watt | 14.9 | 13.1 | 11.6 |
| Multi-GPU Support | Via board | Via board | Via board |
| Street Price | £70 | £60 | £50 |
Analysis
The GCN-powered Cape Verde die is present on the Radeon HD 7770, HD 7750 and, now, HD 7730 GPUs... though not the HD 7790. The Cape Verde implementations are derivated from a 1.5bn transistor core, with differentiation made via snips to the top-end architecture. Particular to this review, HD 7730 loses two Compute Units (128 cores, 8 texture-units) when compared to HD 7750, though both share the same back-end.
Understanding that pricing is absolutely key in the low-end discrete market, HD 7730 can also be outfitted with slower DDR3 memory, reducing price and performance in equal measure. Looking across to what else AMD has in this space, the Radeon HD 6670, which is largely a rebrand of the HD 5670 launched in January 2010, continues to be, on paper at least, a solid alternative to the newer technology. Pushing out a a good number more GFLOPS but losing out with respect to memory bandwidth, the older GPU's VLIW5 architecture may not play as well with modern games that are optimised with the HD 7730's Graphics Core Next in mind.
But there's an APU Dual Graphics CrossFire compatibility issue to appreciate before discarding the 5- and 6-series entry-level GPUs. You see, AMD's latest desktop APU technology, dubbed Richland, uses the best integrated GPU on the market. Known as HD 8670D but based on the same VLIW5 architecture as the 5(6)xx parts, the IGP can only be paired-up with these older GPUs for increased performance; the HD 7730's GCN design is, sadly, incompatible in this instance.
Though appearing decent in the spec table, the £70 asking price of a faster HD 7750 may be well be the main stumbling block to widespread HD 7730 adoption, but let's take a look at the Sapphire card and peruse benchmarks before passing judgement.