|ATI Radeon HD 4770 RV740 DDR5 Video Card|
|Reviews - Featured Reviews: Video Cards|
|Written by Olin Coles|
|Tuesday, 28 April 2009|
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Radeon 4770 Closer Look
Fresh on the heels of a successful Radeon HD 4890 high-end video card launch, ATI has returned to capture middle-market segment. While the HD4890 boasts an impressive RV790 GPU, the new HD4770 offers a newly minted RV740 GPU with 826 million transistors built on a 40nm fabrication process. Taking after the bigger and faster graphics accelerators, the Radeon HD 4770 utilizes a similar layout and design. Closely resembling the Radeon HD 4870 in general outward appearance, the Radeon HD 4770 is actually on par with the Radeon HD 4850 in every other regard. But even with these small feature affinities, the HD4770 is a whole new product with no signs of component 'updates' to give it a new model name.
For example, GDDR5 is currently found only in the HD4870 and HD4890... and nothing more. These two products occupy the top two positions on ATI's single-GPU roadmap, so it's unique to find that a 'refreshed' RV790 version of the HD4850 wasn't also released to fill a GDDR5 gap between the top video cards and the RV740 HD4770. Either way, the GDDR5 video frame buffer memory on the HD4770 operates on a 128-bit ring bus memory architecture, making it half as efficient as the other two iterations of the architecture.
All Radeon graphics cards in the HD 4000-series incorporate the latest ATI Avivo HD Technology for enhanced video display and feature a second generation built in UVD (Unified Video decoder) for the hardware accelerated decoding of Blu-ray and HD DVD content for both VC-1 and H.264 CODEC's, as well as *.mpeg files, considerably reducing CPU loading. The dedicated HDMI adaptor connects through the S-Video port and has 7.1 surround sound support and delivers audio and video output on a single cable for direct connection to an HDMI ready display. Unfortunately, there is no support for the up-and-coming DisplayPort interface on the Radeon HD 4000 series.
The ATI Radeon HD 4000 Series GPUs can all upscale video up to 2560x1600 resolution on capable dual-link monitors, which is almost twice the display resolution of 1080p HDTV displays. This bodes well for all Radeon HD 4000 owners wanting more from Blue-ray movies, but this is just one of the few centerpiece features of the Radeon HD 4770 we're reviewing for this article.
While I am a huge fan of externally-exhausting VGA coolers such as the one used again on the Radeon HD 4770, I wasn't at all pleased with the exposed electronics that were inherent of the stock cooling package. On the other hand, I am also less enthusiastic about internally exhausting coolers which heat internal hardware, even if they do protect the components. Considering the compromise, it seems that ATI has designed an economical thermal solution which is nearly identical to the one featured on their previous Radeon HD 4870/4890 series products.
The cooling unit on the ATI Radeon HD 4770 video card is held tight to the RV740 40nm GPU with the use of a four-corner reinforcing bracket and nine screws. With a die size of 137 mm2, the RV740 GPU offers a diminutive contact footprint with the cooling unit, compared to the 282 mm2 footprint on the RV790 GPU. The double-height cooler does a very good job of cooling the 4770, but there is still a significant amount of heat that builds up on backside of the PCB. If you're an overclocker, there isn't much that can be done to help cool the unit from the reverse side of the circuit board, especially since there are no surface-mounted GDDR5 modules on this side of the video card.
The RV740 operates at 750 MHz by default, and ATI offers top-bin GPUs for factory-overclocked models which run at higher speeds. Unfortunately, the increase in heat output is directly obvious. At idle, the Radeon HD 4770 reference build recorded a warm 54°C, and under load that number raised to 76°C with an ambient room temperature of 21°C. These are nearly the same temperatures we experienced with the Radeon HD 4870 a few months back, which is yet another clue to how similar the RV740 is to the RV770LE.
In our next section we detail our methodology for testing video cards. Following this we offer a cadre of benchmarks to show where the Radeon HD 4770 stands against GeForce and Radeon graphics products... so please read on!