ATI Radeon HD 4770 512MB GDDR5 Review

A Closer Look at the Radeon HD 4770 512MB

The first thing anyone is bound to notice when looking at the HD 4770 for the first time is how much its heatsink differs from past ATI cards. While some of you may be thinking that we received a design with a non-reference cooler; I can assure you that a number of ATI’s board partners will be using this exact heatsink on their initial run of cards. We will take a bit closer look at the heatsink a bit later in this section.

Other than the dual slot cooler and the usual ATI red PCB, there isn’t much to distinguish this card from countless other cards which are on the market today. However, as we take a closer look, you will see that there are a number of interesting differences between the HD 4770 and some other ATI cards.


Past, present and future ATI cards all seem to have different lengths with the new HD 4770 fitting somewhere between the HD 4670 and the HD 4830. Its 8.25” length means it would a perfect fit for mATX HTPCs.


The power distribution section on the back of the card consists of a simple 3+1 phase layout consisting of analog chokes, solid state capacitors and digital VRMs. Considering the fact that the 40nm GPU is supposedly quite efficient, this is a pretty robust layout.

Since the HD 4770 uses about 80W when at full load, ATI needed to use a single PCI-E 6-pin connector. This power connector lies next to one item on the PCB which raises a red flag for me: a 2-pin header for the heatsink fan. While it may not seem like much of a problem at first, in our experience a 2-pin header usually means that the fan speed cannot be regulated which more often than not leads to an annoyingly loud card. It is possible that the card regulates fan speed by way of varying voltage to the connector but we highly doubt it. We will have to see how this affects the overall noise levels of the HD 4770.


The memory modules on the HD 4770 are Qimonda GDDR5 ICs arranged in an 8x64MB pattern. If ATI or one of their board partners chose to, these 64MB chips could easily be substituted out for 128MB units for a total of 1GB of GDDR5. It wouldn’t surprise us one bit to see 1GB HD 4770s making their way onto the market soon after the release date. Interestingly, the hot-running GDDR5 does not have ramsinks installed.


The underside of the HD 4770 512MB doesn’t really hold anything of interest other than the retention bracket for the heatsink. It should be noted that the spacing between the retention bracket’s holes is 45 mm. This means that while some older heatsinks will fit (any heatsink compatible with the X1650 or 8600GT), newer ones compatible with the HD 4800-series will not fit.


As with most ATI cards, the HD 4770 uses standard Crossfire connector which can be used to link two cards together for some extra performance. Meanwhile, the backplate has the usual single HDTV Out connector and dual DVI-D outputs.