PCB Design and Cooling System
Like all top-performance discrete graphics solutions these days, the product from Diamond is in fact a copy of the reference card and does not differ in anything from any other ATI Radeon HD 2900 XT irrespective of the amount and type of graphics memory. You can see it in the following photograph.
There are no external differences whatsoever. It’s impossible to tell if the given model of ATI Radeon HD 2900 XT comes with 1 gigabyte of graphics memory. You can only learn this from the green sticker on the reverse side of the PCB. Besides serial numbers the sticker reads the card model, which is “ATI RADEON HD 2900 XT 1GB” here. The sticker with the company logo on the cooler is the single indication that we are dealing with a product from Diamond.
The GPU of the Diamond Viper HD 2900XT 1024MB GDDR4 is not overclocked and works at a frequency of 742MHz. It has a standard configuration with 64 superscalar computing units with 5 ALUs in each (for a total of 320 ALUs), 4 texture processors (equivalent to 16 TMUs), and 4 raster processors (equivalent to 16 ROPs). There are no differences from the ATI Radeon HD 2900 XT 512MB GDDR3.
Memory is the only component that sets the two ATI Radeon HD 2900 models apart. The total amount of memory being 1024MB on this card, it carries sixteen 512Mb chips of GDDR4 memory (Samsung K4U52324QE-BC09, 16Mb x 32). The BC09 suffix indicates the slowest model in the series, but it has a rated frequency of 1100 (2200) MHz which is more than enough for the ATI Radeon HD 2900 XT 1GB GDDR4. The Diamond version of the card has a memory frequency of 1000 (2000) MHz, so there’s a small headroom for overclocking left.
The Diamond card has no other difference from the reference ATI card and its design is identical to that of any other Radeon HD 2900 XT. The card is equipped with ATI’s reference cooler whose design was described in our review of ATI’s new graphics architecture called Highly Defined: ATI Radeon HD 2000 Architecture Review. This design with a blower and the exhaust of hot air outside the system case is the most optimal one today in terms of size/performance ratio and is employed by both ATI/AMD and Nvidia.
Using a copper heatsink, the ATI cooler has somewhat worse noise characteristics than the reference cooler of Nvidia’s GeForce 8800 series in 3D applications. It can be easily explained if we recall the fact that the R600 has huge power consumption, over 160 watts in 3D mode. It generates a lot of heat and ATI had to achieve the required cooling efficiency by speeding the fan up since the heatsink could not be enlarged much more. As a result, the Radeon HD 2900 XT has normal dimensions but produces more noise than the GeForce 8800 GTX/GTS. The new card is easy to hear among the noise from other system components in 3D mode.
Like any other ATI Radeon HD 2900 XT, the Diamond card is equipped with two DVI-I ports (with support of audio-over-HDMI), a universal YPbPr/VIVO port, and two CrossFire connectors. Power is supplied to the card via two connectors: a 6-pin and an 8-pin one. The latter connector is loaded the most,a s we have already found out from this article, but you can plug a 6-pin connector into it – this will only deprive you of the opportunity to overclock the card using with the standard options found in the ATI Catalyst driver. All other overclocking tools are going to work normally.