Radeon HD 5770, Radeon HD 4890, And GeForce GTX 275 Overclocked

ATI Radeon HD 5770: Memory With A Need For Speed

Click the image below to launch the image gallery For ATI's Radeon HD 5770.

Wearing a black shroud, the Radeon HD 5770 is a rather inconspicuous card. Don’t be fooled, though. Beneath that classy exterior lies a veritable panther with very sharp claws. Our test results are clear: the Radeon HD 5770 is perfectly capable of replacing the Radeon HD 4870. This new card is quieter than its predecessor and draws less power, too. Indeed, both in 2D and in 3D mode, the HD 5770 consumes about 50 watts less power than the 4870, while offering virtually the same performance in 3D games. Since it is manufactured on a 40nm process, the GPU never runs at more than 69 degrees Celsius, which isn’t much of a challenge for the cooler. Consequently, the card purrs along at an audible but unobtrusive 39 db(A).

Actually, we’d be hard pressed to identify a single drawback compared to the older card. What’s not to like? The new model consumes less power, produces less heat, runs quieter, supports DirectX 11, and offers performance that rivals that of the HD 4870, even with the first batch of drivers. Connectivity is good, too. The card sports two DVI connectors, one HDMI, and one DisplayPort output.

The real focus of this article is overclocking MSI’s GTX 275 and HD 4890. However, since we had a reference Radeon HD 5770 handy, we decided this would be a good opportunity to see how far we could push ATIs newest generation of mainstream cards. At stock speeds, our reference card clocks the GPU at 850 MHz and the memory at 1,200 MHz. ATI opts for GDDR5 memory for all members of the Radeon HD 5000-series (so far), although the memory bus is only 128-bits wide on this model.

We used ATI's own Catalyst graphics driver for our overclocking experiments, since its Overdrive utility offers plenty of headroom. As it turned out, our sample’s GPU was already close to its limit. We started off with a GPU frequency of 920 MHz, which we had to reduce to 895 MHz to stabilize the card. The memory was a completely different matter, though, and offered exceptional potential. Back in the days of the 4000-series, you considered yourself lucky if you managed to squeeze out an extra 10 percent margin by reaching 1,200 MHz. Our Radeon HD 5770 allowed us to set the memory frequency to no less than 1,445 MHz, which we had to lower slightly to 1430 MHz to ensure stability. An overclock from 1,200 MHZ to 1,430 MHz means a clock speed increase of 19.2 percent. Not bad at all for a mainstream card. 

As mentioned, the Radeon HD 5770 is already tied with the HD 4870 at stock speeds. Once it is overclocked, though, it gains another eight percent. That’s still a few percentage points short of the Radeon HD 4890's performance, but certanily not an insurmountable gap that could conceivably made up by driver-based improvements to the 5770.

However, the really good news here is that overclocking has no adverse effect on 2D power consumption or noise, since the card reverts to the same lowered clock speeds as before. Under load, its temperature only increases from 69 to 72 degrees Celsius, causing the fans noise level to rise from 39 to 40.5 db(A). But here’s the surprise: power consumption only increases by a mere 6 watts, showcasing the benefits of a 40nm production process. 

ATI has outdone itself. The Radeon HD 5770 is really a fully-featured card, combining 1GB of fast GDDR5 memory, a much lower power consumption, low noise levels, an optimized driver with a real 2D mode as well as good overclocking capabilities, a well-balanced fan speed profile, HDMI and DisplayPort connectivity in conjunction with DVI, and DirectX 11 support.