The card has a new heart indeed. Manufactured on today’s thinnest 40nm tech process, the RV470 die is only 137 sq. mm large. It is the smallest of today’s consumer GPUs.

This 826-million-transistor cutie features grownup resources including 640 unified shader processors, 32 texture-mapping units and 16 rasterization modules. Thus, the HD 4770 is functionally equivalent to the Radeon HD 4850 and HD 4830 which is currently leaving production lines. As opposed to the HD 4830’s 575MHz frequency, the HD 4770 has a GPU frequency of 750MHz! Moreover, the 40nm tech process brings a promise of high overclockability which could not be had from the HD 4830. I can also add that the card drops its GPU frequency to 250MHz in 2D mode.

The reference HIS Radeon HD 4770 is equipped with 512 megabytes of graphics memory in eight GDDR5 chips located on the face side of the PCB.

The use of GDDR5 chips in an entry-level product ($99) sets a precedent because no other maker has installed such potentially fast memory on graphics cards of this class. The memory bus is 128 bits wide. The Qimonda IDGV51-05A1F1C-40X chips are dated the 36th week of 2008 and work at a frequency of 3200MHz. The rated frequency of these chips is 4000MHz, so they may be good at overclocking. I will check this out shortly.

GPU-Z reports the full specs of this card.

The coolers of the graphics cards covered in this review were tested in a closed system case at an ambient temperature of 24°. The cards’ temperatures and frequencies were monitored with RivaTuner 2.24 excepting the Radeon HD 4770 which is not yet supported by RivaTuner and was monitored with GPU-Z. Each card was loaded by FurMark version 1.6.5 running in stability mode at 1280x960. This test loads the GPU very heavily. It ran for about 15 minutes until the GPU temperature fully stabilized. I used Arctic Silver 5 thermal grease as I had dismantled the cards before the tests.

So, the cooler of the HIS Radeon HD 4770 is an aluminum fan-like thing painted the color of copper. The heatsink is cooled with an 80mm fan and has a plastic cap. The cooler was quiet most of the time but would give out an occasional wail for a couple of seconds. Its performance was good enough, though:

Unfortunately, the Arctic Cooling Accelero Twin Turbo could not be installed on the Radeon HD 4770 as it did not fit the latter’s size so I instead installed a Thermaltake S-Orb which helped reduce the GPU temperature by as much as 23°C.

As you can see, the GPU temperature of the Radeon HD 4770 512MB (at 750/3200MHz) is no higher than 47°C under FurMark! This is an impressive result, so it’s time to check the cards out at overclocking.

I overclocked them with Catalyst Control Panel and GPUTool.

Alas, the results are not very good. The GPUs could only be overclocked to 850 and 865MHz. The graphics memory could be overclocked to 3340MHz on one card and could not be increased at all on the other.

Of course, that’s not what you can expect from a 40nm GPU and GDDR5 memory. The memory chips behaved oddly: they could work at a high frequency but then would hang the system at a lower one. After I finished my tests, ATI released a new BIOS for the reference Radeon HD 4770. Users report that this BIOS helps overclock the card’s memory better. Perhaps we will check it out in a future review.

The Radeon HD 4770 has a recommended price of only $99.