Radeon HD 5570 and 5550 GDDR5: PCB Design and Specifications
The Radeon HD 5770 is usually equipped with DDR3 memory. One such model was covered in our earlier article. But as we noted in the mentioned review, there also exist versions of Radeon HD 5570 and HD 5550 cards with GDDR5 memory but lower frequencies and with somewhat cut-down configurations. We’ve got a couple of such cards and will have a closer look at one of them, namely at the Radeon HD 5570 GDDR5, because both are designed in the same way.
As opposed to the above-described card from Gigabyte, this one is a full-size, even though rather short, graphics card that can hardly be installed into a low-profile system case unless the latter allows to turn the PCI Express x16 slot around by 90 degrees by means of a riser. The Radeon HD 5570 GDDR5 has a dual-slot cooler which is rather large for such a modestly positioned and priced product.
The PCB design is obviously meant for some more advanced graphics card. It doesn't resemble the Radeon HD 5670s that we have tested in our labs. There are a lot of empty spaces on the PCB and, surprisingly, there is a seat for an external power connector although Redwood-based solutions are known to do well without external power because this GPU is highly economical. The GPU voltage regulator is based on an uP6201 controller whereas the memory voltage regulator is managed by an uP6101 chip. These controllers are both located on the reverse side of the PCB.
Each card comes with four 1Gb Samsung K4G10325FE-HC05 memory chips which can be found on many modern graphics cards. Their rated frequency is 1000 (4000) MHz. The four chips make up a total of 512 megabytes of graphics memory accessed across a 128-bit bus. Theoretically, Radeon HD 5570 and HD 5570 cards with GDDR5 are supposed to have memory frequencies of 900 (3600) MHz and 800 (3200) MHz, respectively, but our samples both have a memory frequency of 1000 (4000) MHz, providing a peak memory bandwidth of 64 GBps. This is much higher than that of the above-described Gigabyte GV-N430OC-1GL (28.8 GBps).
The Radeon HD 5570 and 5550 GDDR5 feature the RV830 Redwood processor which was discussed in our review called ATI Radeon HD 5670, Radeon HD 5570 and Radeon HD 5450: A Multimedia Ideal? Despite the rather massive cooler, there is no protective frame on the GPU die. The GPU frequencies and configurations coincide with AMD’s official specs. The GPU works on the Radeon HD 5550 in a cut-down configuration with 320 ALUs and 16 TMUs whereas the Radeon HD 5570 is no different from the Radeon HD 5670 in anything other than frequencies. In this test session the GeForce GT 430 will be competing with the Radeon HD 5550 GDDR5 in the first place, the latter being inferior in texture-mapping performance but much faster in terms of scene fill-rate.
Each of these Radeons has three video connectors: DVI-I, HDMI and DisplayPort. We guess this configuration is adequate today as it doesn't include an outdated D-Sub, especially as analog connection can still be established by means of the DVI-I port and an appropriate adapter. Interestingly, there is a seat for a second DVI connector on the PCB. If it were installed, it would be located in the second tier of the mounting bracket above the first such port. It is also interesting that each card is designed to support CrossFire, although CrossFire connectors are often missing even on many versions of the more advanced Radeon HD 5670.
The cooling system of each card consists of a solid aluminum heatsink with an 80mm fan from Arctic Cooling. This should be more than enough to cool an RV830 chip working at a reduced frequency.
The lack of some elements on the PCBs of these cards suggests that they are some prototypes that can hardly be found selling in shops. Anyway, we are interested in learning how fast Radeon HD 5570/5550 cards with GDDR5 memory may be, so we are going to benchmark them today.