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Page 1 of 3   With new Radeon HD 5850 and HD 5870 models introductions, ATI also announced when and what models will be presented in the near future. Therefore, it was obvious that new generation begun with Cypress GPU, with code name RV870, which continued with Juniper GPU with code name RV840 GPU. With HD 5770 and HD 5750, along with HD 5870 and 5850 models, ATI has covered high and mid range DirectX 11 graphics cards market. When we take a look at specifications, it is clear that there is nice gap between high-end models with 1600 (HD 5870) and 1440 (HD 5850) Stream Processors and more powerful model from mid range that has 800 Stream Processors (HD 5770). Nevertheless, even with Stream Processors cut to half this model can be very interesting to users that want something more than average performance levels but don’t have big budget. Model HD 5770 is more powerful representative in mid range, and very similar to HD 4850 and HD 4870 models. Price tag should be somewhere between last two models, while we will see how good this new card performs.
ATI Radeon HD 5770 is based on Juniper GPU that has 800 Stream Processors, 40 Texturing units and 16 ROP units. If you take a look at specifications of earlier generation GPUs, that were used on HD 4850/4870 models, you will see that these two GPUs have same specifications. On the other side, some other features of new model are not based only on raw processing power. First of all, new manufacturing process has lowered power consumption so you don’t need to purchase expensive power supply unit any more. Efficiency is vastly improved so maximum consumption goes up to 108W while minimal is measly 18W (someone sad Radeon Mobility 5770?). Compared to HD 4870 and its 160W of maximum power consumption level and 90W of minimal, this is great result. Of course there are new technologies implemented as on model HD 5870 , but most important is support for DirectX 11.
Model that we got in our test lab is signed by PowerColor. It differs from referent model by sticker that was, in case of our sample, obviously, applied in a hurry. This card looks as shrunk HD 5870 model with huge plastic cover over the cooler. Cooler is made out of aluminum with copper base and turbine fan that is a bit noisier that we would like it to be. Of course, there is manual control, so we suggest you to thinker a bit with fan rpm, as we did. We found out that 50% of maximum is enough when this card is placed in chassis with good airflow. GPU itself is significantly smaller than Cypress GPU, which resulted in relatively smaller PCB. Since GDDR5 memory is used, memory bus can be 128bit wide, with memory bandwidth set somewhere between HD 4850 and HD 4870 models. Memory frequency is set to 1200MHz (which is effectively 4800MHz). On our model, there was 1GB of memory, which will support higher resolutions, while models with 512MB will be best suited for users with monitors that have smaller resolutions. GPU is set at 850MHz, which is pretty high. This provides performances that are higher than HD 4850 model, while texture and pixel fill rate will be higher even compared to HD 4870. All this implies that we can expect performance level somewhere between HD 4850 and HD 4870 graphics cards. With overclock this performance levels can be elevated even to higher levels than those.
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