According to the Steam statistics, midrange or even entry-level graphics cards are the most popular among gamers. Apart from integrated graphics, we see such discrete solutions as Nvidia GeForce GTX 560/GTX 460 and AMD Radeon HD 5770 at the top of the list. AMD even holds that the Radeon HD 5770 is the absolute bestseller among DirectX 11 compatibles, enjoying as much as 28 percent of the market.
Although such marketing claims should be viewed with caution, we have to acknowledge that the HD 5770 and, later, HD 6770 is indeed a highly successful product thanks to its attractive price/performance ratio. That’s why AMD’s Tahiti GPU from the Southern Islands family was quickly followed by the Cape Verde and such graphics cards as Radeon HD 7770 GHz Edition and Radeon HD 7750. And it’s only then that they announced the Pitcairn. So today we are going to review and benchmark the junior products based on Southern Islands GPUs.
Architecture and Positioning
AMD seems to have got a complete line-up of Southern Islands GPUs and graphics cards now. The top market segment is occupied by the Tahiti and such cards as Radeon HD 7970 ($549) and HD 7950 ($449). The midrange products include the Pitcairn-based Radeon HD 7870 GHz Edition ($349) and HD 7850 ($249). The entry-level offers are the Radeon HD 7770 GHz Edition ($159) and HD 7750 ($109) based on the Cape Verde GPU.
The bottom market segment is still populated by products with the previous-generation Northern Islands GPUs.
Talking about the Cape Verde, this 28nm GPU is the smallest in the new line-up at only 123 sq. mm. The next slide shows this clear enough.
At the same time, its functionality is just the same as that of the Radeon HD 79xx series:
It’s based on the modern Graphics Core Next architecture, even though with significant simplifications due to the reduced manufacturing cost. For example, the senior variant, Cape Verde XT, has only 640 unified shader processors, 40 texture-mapping units and 16 raster operators, and its memory bus is only 128 bits wide:
However, the new 28nm tech process permits to clock this GPU at a high frequency and endows it with high overclocking potential as is indicated by the next slide:
AMD also puts an emphasis on the energy efficiency of the new products. The Radeon HD 7770 GHz Edition has a typical power consumption of 80 watts while the junior Radeon HD 7750, only 55 watts. With the monitor turned off, these cards are expected to consume no more than 3 watts.
As for multi-GPU technologies, the next slide promises a twofold increase in performance in CrossFireX mode:
The 128-bit memory bus just won’t let the CrossFireX configuration be too fast, though.
The new cards’ specs are listed in the table below in comparison with AMD Radeon HD 7850, Radeon HD 6870, Radeon HD 6770 and GeForce GTX 560: