Power consumption
Power efficiency has been a big trend in the computing industry. Terms like “performance per watt,” “dollars per watt” and “green computing” all point towards the market’s desire for more horsepower on less juice. ATI has listened, and the Radeon HD 5800 series is one of the most power-efficient enthusiast GPUs the company has ever produced.
The biggest reduction in power consumption is owed to the transition to a 40nm process node. GPUs built to 40nm quite simply use less power than their 55nm predecessors. As a result, the new Radeons consume just 12% more power (188W peak) than the 4870 (160W peak), but at twice the performance. By any measure, this directly translates to an incredible improvement in power efficiency.
The move to 40nm has reduced idle power consumption as well. While the Radeon 4870 consumed around 45W idle, the 5870 consumes just 27W with no GPU load. ATI has also taken advantage of Windows Vista and Windows 7’s “Linked Adapter” mode to detect underutilized GPUs in a CrossFire environment. These underutilized GPUs can achieve an even lower power state, which takes consumption well below 27W.
The 5870 offers a net power reduction over the 4870.
The other major reduction in power consumption is owed to a brand new memory controller. The Radeon 5870 packs 1GB of high-frequency GDDR5, and that can gobble up juice in a hurry. To keep VRAM power consumption in check, ATI has implemented a so-called “low strobe” mode. This mode forces the GDDR5 to act much like GDDR3, which requires less power. This low power mode is perfect for non-3D instances where the GPU’s full 4.8Gbps of memory bandwidth isn’t required. In this state, the GPU has just 0.6Gbps of memory bandwidth, but it can be kicked up to full blast in an instant.
The 5870 doubles the performance of the 4870 per watt.
Noise and heat
The switch to 40nm has also had an effect on the GPU’s heat output in the form of a big reduction over the previous generation. ATI has followed this improvement with a commensurate improvement in cooling, resulting in lower temperatures and lesser noise.
While the Radeon 4870 could easily reach temperatures north of 70°C under full load, the 5870 should regularly stay within 40-50°C in a well-ventilated case. These frosty GPU temps, says AMD, are owed in part to a larger GPU with an increased heatsink surface area. A bigger heatsink simply dissipates more heat. The larger player in reducing heat, however, is the 40nm chip itself. Smaller chips require less voltage than bigger ASICs, and less voltage means less heat.
Some would think that higher performance with lower temperatures leads to increased fan noise, but that’s not so according to AMD. The firm has redesigned the fan to use newer bearings that produce a lower tone. These new bearings are scarcely audible at low speeds, and aren’t quite as piercing at maximum RPMs.
Lastly, the fan’s velocity has also received an overhaul. The new cooling system on the 5870 can run as low as 1200 RPM, and that’s a lot less than the 4870 before it. Even at maximum velocity, says AMD, the fan is still slower than the one used on older Radeons.
All of these changes to thermal output, the heatsink and the fan mean the 5870 is a whisper compared to the noisy blast furnace it’s replacing.
Other considerations
Beyond direct improvements to 3D and thermal performance, the 5870 is also the world’s first video card capable of processing Dolby TrueHD and DTS-HD MA offered by select Blu-ray titles. This was a task, which, until today, required an extremely expensive sound card and a nightmarish level of tinkering with software. While the 5870 is obviously not an HTPC card, it will soon be followed by smaller and less expensive models that will fit that bill. This audio prowess–combined with complete H.264, VC1 and MPEG-2 offloading and an HDMI port–makes the Radeon HD 5800 series the most advanced and complete HTPC A/V solution on earth.
The 5000 series is also the first GPU to support what ATI calls the “Single Large Surface,” or SLS. It’s a technique that seamlessly combines multiple monitors into a single display at the driver level. Users who have fussed with tri- (or higher) monitor setups know how difficult these configurations can be, but the 5000 series makes quick work of it.
ATI has given this technology the “Eyefinity” name, and promises it will greatly simplify the use of as few as two, or as many as nine displays. It’s all a matter of personal preference, of course, but $600 in 22? displays may be a fair sight better to some than a single larger monitor for the same price.
Lastly, and perhaps most importantly, ATI is currently the only provider of DirectX 11 GPUs. DirectX 11 is the next iteration of the Microsoft DirectX architecture, and is a collection of common application programming interfaces, or APIs, that standardize the way code for a GPU is written and executed.
As a result of DirectX, and its “competitor” OpenGL, users across the globe can run any game on any GPU from any company. Whether or not that game runs well depends on the hardware’s horsepower, but DirectX has helped to avoid a standards war not unlike the one that divided Blu-ray from HD-DVD.
As the eleventh major entry into the DirectX annals it’s not quite as drastic as DirectX 10 that came before it. While DirectX 10 was all about dramatic improvements in lighting and texturing, DX11 is a more subtle movement that emphasizes GPU-accelerated apps and refined scene detail. Its easier implementation and higher predicted deployment rates make it a technology you need to know about.
Numbers, numbers, numbers
The new Radeons were set to launch today, and the stroke of 12:01 AM on September 23 means a flood of benchmarks have hit the scene to answer everyone’s burning performance questions. We’ve hand-picked several of them from the sites that consistently offer a high degree of integrity and accuracy, so you can answer those questions too.
Wrap up
ATI now stands unchallenged in Blu-ray audio processing, power consumption, single GPU performance, and performance per watt, DirectX 11, multi-monitor setups, anti-aliasing performance, and anisotropic accuracy. By any measure, the confluence of these qualities easily makes the Radeon HD 5000 the most significant shakeup of the GPU market in the last two years.
Given that rival firm NVIDIA isn’t expected to hit back until at least November, GPU enthusiasts need not–cannot–look further than ATI to power their next rig. This is an incredible architecture.
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