The Radeon HD 5850 is ATI's videocard of choice for the gamer on a budget. It takes over where last generation's price/performance darling, the Radeon HD 4850, left off. It's also happens to be in the highest echelon of AMD's new Vision platform initiative, where it's paired with AMD 890FX-based motherboards and Phenom II X6 CPUs. While a standard Radeon HD 5850 videocard is exciting enough to get us perked up and paying attention, ASUS has brought its special sauce to the table with a special edition called the EAH5850 DirectCU TOP. Speeds aren't the only thing ASUS changed, however...

One of the differences ASUS mentions between this videocard and the standard Radeon HD 5850 is that the EAH5850 DirectCU TOP comes with specially screened GPU and Samsung DRAM, both of which are pre-overclocked right out of the box. The Radeon HD 5850 GPU has been bumped up from the default 725MHz up to 765MHz, and the memory from 1000MHz up to 1125MHz. Thanks to quad-pumping, this means ASUS EAH5850 DirectCU TOP's memory runs at an effective 4500MHz! ASUS has also fitted this PCI Express x16 videocard with a custom thermal solution that places two 8mm diameter copper heat pipes in direct contact with the Radeon HD 5850 silicon. It's the same approach many top-notch CPU coolers use.

In the Grand Hierarchy of Gaming Videocards, the Radeon HD 5850 is just one rung under ATI's flagship, the Radeon HD 5870 - a videocard only spoken off in hushed voices among serious gamers. Both are based on ATIs 'Cypress' GPU, with the 40nm Radeon HD 5850 being a slightly stripped down version of its bigger brother. The Radeon HD 5850's RV870 GPU has 1440 stream processors, 72 texture units, and a 256-bit wide memory bus that connects it to 1GB of GDDR5 memory.

Like all other Radeon HD 5000-series graphics cards, the EAH5850 DirectCU TOP has native DirectX 11 support and is Crossfire compliant. DX11 brings major new features like tessellation, which can be used to greatly increase the details and complexity of 3D geometry, and compute shaders which can allow the GPU to calculate things like pathfinding AI and physics. Other new features of included in the DirectX 11 standard are texture limits as high as 16K, better support for parallel processing (for Radeon videocards in Crossfire mode), and a redesigned, more versatile rendering pipeline. The Radeon HD 5850 is also compatible with Shader Model 5.0, as well as OpenGL 3.2. Expect to find the pre-overlocked ASUS EAH5850 DirectCU Top/2DIS/1GD5 videocard in the wild for about $315 CDN ($315 USD, £210 GBP), depending on the retailer.

ASUS EAH5850 DirectCU Top/2DIS/1GD5 Videocard INCLUDES: User's Manual, Driver CD, Utility CD, molex-to-PCI Express converter, HDMI to DVI converter, DVI to VGA converter, ATI CrossfireX bridge Graphics Processor: ATI Radeon HD 5850 (765MHz) Memory Capacity: 1GB GDDR5 (4500 MHz) Card Format: PCI Express x16 2.0, two slots wide. Outputs: DisplayPort, HDMI, DVI-D Videocard Class: Enthusiast

Like most Radeon 5000-series videocards, the ASUS EAH5850 DirectCU TOP supports onboard hardware HD decoding technologies. ATI's AVIVO HD video technology allows the GPU to process video streams using the Universal Video Decoder. It also supports ATI Stream acceleration, with OpenCL and DirectCompute support for applications like video encoding.

With manufacturer selected GPUs and memory, ASUS has designed the EAH5850 DirectCU TOP for serious overclocking. The included software CD comes with a copy of ASUS' SmartDoctor overclocking suite, which allows for dynamic overclocking of the GPU core and memory clock speeds, as well as the ability to over volt the GPU's Vcore. We've come a long way from the days of having to flash a videocard's BIOS in order to eke out a few more MHz from our GPUs. While ASUS SmartDoctor software does the trick, the GUI very badly laid out, the slider bars and numerical values too small, and too much space is devoted to flashy graphics and bar charts that are completely unnecessary. ASUS really ought to redesign the software package it bundles with overclocking videocards is devotes so much time to building fast - this junky looking software tool is just a travesty!

Video outputs on the ASUS EAH5850 DirectCU TOP include the standard DVI, HDMI and a newer standard called DisplayPort. Display Port will eventually replace DVI as the standard interface for computer monitors, but right now most of you are likely to have DVI, and possibly HDMI only. Display Port is designed for increased bandwidth rates that go up to 17.2Gb/s, and it uses this extra data space to support multiple high resolution monitors - as in ATI eyefinity. Display Port can also be daisy-chained, so a single display port output can be connected to a Display Port compatible monitor, and that monitor can then be connected directly to another monitor, and so on.

Video outputs: HDMI, display port and DVI.

As this card stands, it will support up to three monitors (with resolutions up to 2560x1600) at once using its Display Port output. This videocard will also support newer 120Mhz monitors designed for 3D stereoscopic gaming, as well as ATI's own Eyefinity gaming modes that allow monitors to be 'tiled' together to form one massive display. Of course if you don't have a DisplayPort-based monitor you can still use the ASUS EAH5850 DirectCU TOP, since it also has both DVI (max resolution 2560x1600) and HDMI (1920x1200) video outputs. Naturally, the HDMI 1.3 output will also carry audio if connected to a compatible display or receiver. ASUS also includes HDMI to DVI adapter and DVI to VGA adapter, just in case you have an older secondary display.

The ASUS EAH5850 DirectCU TOP uses a PCI Express 2.0 x16 connection to transfer data to and from the system. If you have a compatible motherboard with dual PCI Express x16 or x8 slots, you can use the included Crossfire bridge to hook up another Radeon HD 5850 videocard in CrossfireX mode.

The ASUS EAH5850 videocard will operate with two 6-pin PCI Express power connectors only, if you don't have an 8-pin and 6-pin available.

On the rear end of the medium size, double slot wide ASUS EAH5850 DirectCU TOP videocard you'll find an 8-pin PCI Express power connector and a 6-pin PCI Express power connector. The videocard comes with an molex-to-6-pin PCI Express power adapter too. PCSTATS was able to run and overclock the EAH5850 DirectCU TOP without any difficulties using just a pair of 6-pin PCI Express power connectors, although you may want to connect an 8-pin PCI Express power connector for maximum overclocking results.

Exposed Heatpipe Thermal Solution for a Videocard

Exposed 8mm diameter heatpipes contact the large silicon die of the Radeon HD 5850 GPU.

The design of the ASUS EAH5850 DirectCU TOP's heatsink differs from the monolithic heat shroud design found on reference ATI Radeon HD 5850 videocards. The shorter design doesn't quite exhaust hot air all the way out of the computer chassis, but any problems this might cause are easily remedied by having a secondary system fan to lower internal case temperatures.

ASUS uses a thermal solution called DirectCU to cool the overclocked Radeon HD 5850. DirectCU uses a pair of cooper cooling pipes that make direct contact with the silicon of the GPU. This heat is conducted along 8mm heatpipes to an array of aluminum fins that are in turn cooled by the integrated fan.

Next up, the ATI Radeon RV870 Cypress GPU and overclocking results!