Board analysis

Before we get into the cards themselves, a couple of quick items we should point out.

First, the cards represented here are based on ATI’s first-generation Radeon 5770 reference design and cooling. This includes ATI’s “Phoenix” shroud.

The Phoenix shroud, as ATI calls it, is designed to exhaust hot air outside your system case. It’s a dual-slot cooler that consists of a dual-slot aluminum heatsink with a copper baseplate used to draw heat directly off the GPU. The key ingredient found on Phoenix is its black plastic duct. This is used to channel hot air from the graphics card out the back of the case, as well as other portions of the card.


ATI has since replaced Phoenix with an egg-shaped cooler that looks similar to the one used on the less powerful Radeon 5750. The egg-cooler used on newer second-gen Radeon 5770 cards employs an Orb-shaped dual-slot heatsink with the addition of a heatpipe. The heatpipe is made entirely from copper, which helps to increase its effectiveness. The heatsink itself is made from aluminum and helps keep the heatpipe cool.

The overall size and shape of this newer cooler reminds us a lot of Zalman’s VF900 VGA cooler.

Because it isn’t enclosed inside a duct, the second-generation cooler doesn’t exhaust hot air outside your case. As a result, your case temps will be hotter.

Fortunately it appears the newer cooler does a better job of cooling the GPU itself than the first-gen card. Expreview ran some head-to-head benchmarks, and found the 2nd-gen cooler offered GPU temps that were around 9 degrees Celsius cooler at load. PCB temps were cooler as well. Case temps were up slightly, but this is honestly going to vary from case-to-case. Systems with better ventilation will obviously show more subtle differences between the two coolers than smaller, cramped cases.

First-generation Radeon 5770 CrossFire configs with the Phoenix shroud would likely run cooler as well.

Both the first and second generation Radeon 5770 boards run at the stock Radeon 5770 reference speeds. Right now ATI is limiting all their board partners to the same (stock) clock speeds and cooling. As a result, there’s very little differentiation amongst the various 5770 boards currently on the market: they’re all 100% identical from a pure hardware perspective.

In the coming month or so, we should see the first custom 5770 boards begin to trickle on to shelves, but from what we understand even these upcoming boards won’t be OC’ed very far from the speeds of today’s boards.

With that out of the way let’s look at the cards we’ve gathered for today’s article.

ASUS Radeon 5770 Voltage Tweak

From ASUS we have their Radeon 5770 Voltage Tweak board. The Voltage Tweak card has a number of software-related enhancements that put it ahead of the other 5770 boards on the market in our opinion.

For starters, if you boot up ATI’s Overdrive utility found in Catalyst Control Center, you’ll find higher limits for OC’ing than other 5770 cards. Most Radeon 5770 cards are limited to max OC speeds of 960MHz core/1445MHz memory in Overdrive. However, the graphics core on the ASUS Voltage Tweak board can be clocked up to 1200MHz!

The second distinguishing feature that the ASUS Voltage Tweak board offers is ASUS’ Smart Doctor software. With Smart Doctor you can adjust the GPU voltage. Smart Doctor can also be used to OC the graphics core and memory, as well as monitor temps.

ASUS provides sliders for GPU/memory clock speed adjustment, as well as GPU core voltage adjustment. The GPU/memory clock speed sliders top out at the same max settings as ATI’s Overdrive, so nothing new here, but the GPU voltage adjustment is unique and pretty powerful. You can crank the core voltage all the way up to 1.4V (default voltage is 1.125V) in increments as fine as 0.002V.

Adjusting clock speeds and voltages is ridiculously simple. Just dial in the settings you want, and click the “set clock” button in the bottom of Smart Doctor and voila you’re done.

You can also use Smart Doctor to adjust fan speed settings, although for some weird reason ASUS hides the slider for fan speed adjustment within a separate submenu. In our opinion this slider should be provided right alongside the others. Here you’ll also find options for other Smart Doctor features such as Overheat protection, Smart Cooling, hardware monitoring, and ASUS HyperDrive, although the implementation is toned down in comparison to previous ASUS Smart Doctor offerings we’ve reviewed in older GeForce and Radeon cards. Quite simply many of these features aren’t needed anymore because they are now supported natively by the GPU.

While we’ve always been big fans of ASUS’ Smart Doctor software, it would’ve been nice if it offered custom profiles and the ability to save your OC’ed settings; each time you reboot you have to start over. Presumably you can use ASUS’ GamerOSD software to perform these functions, but we aren’t big fans of the interface ASUS has implemented for this utility and would rather get it all from within Smart Doctor.

PowerColor Radeon 5770

While the ASUS 5770 Voltage Tweak board will appeal to the enthusiast crowd who wants to OC, value-conscious consumers may not want to pay the premium ASUS charges for their 5770 board, especially since all of the Radeon 5770 cards on the market are identical to each other anyway.

Therefore if you consider yourself one of those users, and would like to save a little money, you may want to opt for PowerColor’s 5770 offering, which is one of the least expensive cards on the market at the moment.

PowerColor’s 5770 currently sells for $164.99 on Newegg right now, just $2 more than the cheapest 5770 card, which comes from HIS.

Again, it’s the exact same hardware as the ASUS board, and every other Radeon 5770 card on the market, just cheaper.


So if saving money is important to you, PowerColor’s Radeon 5770 board is one of the more compelling choices on the market right now.


Neither card ships with a game bundle, so no voucher for DiRT 2 here. You will get the usual assortment of hardware accessories however, with both cards shipping with the DVI-to-VGA adapter, CrossFire cable, and other assorted goodies you expect nowadays.