Introduction

A few months ago AMD released their new Radeon HD 5800 Series of graphics cards which quickly became a big success due to the numerous improvements made over previous generations. Up to recently all cards available from all manufacturers were reference design cards which means they were all made to the same specifications, using the same components and then a sticker was added on the cooler depending on the AIB.

Now we are seeing more and more custom designed HD 5850 cards that use both a non-reference cooler and a non-reference PCB design. While this allows for considerable production optimizations and reduction in manufacturing cost it also introduces the risk that the product might not work as optimally as intended by AMD.

With this card ASUS is introducing a new cooler concept called "DirectCU". The basic design princicle is that the cooler's heatpipes make direct contact with the GPU die - without any cooling baseplate in between. According to ASUS the new cooler delivers better cooling performance at less fan noise than the reference design. ASUS has also increased the clock speeds to 765 / 1125, which is a decent, but not spectacular increase over the reference values.

When comparing this card to the ASUS EAH 5830 DirectCU that we reviewed recently, the only difference is the GPU core and the red stripes on the cooler. The PCB design and component selection is 100% identical. Of course both cards have a different BIOS with different clock, voltage and fan settings, but otherwise the cards are the same.

Packaging & Contents

We received a card without retail packaging or accessories.
Products in retail will come with the usual acessories like driver CD, adapters etc.

According to ASUS, an HDMI to DVI adapter is included in the box that will enable you to use two DVI ports.

The Card

ASUS is using a new cooler that is designed to combine low fan noise and cooling performance at an affordable price. You can immediately see the heatpipes coming out of the thermal assembly, conveying a feeling of cooling power.


Just like the reference design, the ASUS EAH5850 TOP DirectCU uses two slots in your system.


The card has one DVI port, one HDMI port, and one DisplayPort. This is just one of many output configurations that are possible on the new cards, thanks to the overhauled display output logic. Basically the card can drive six TMDS signals that can be combined in any way (a dual-link DVI consumes two TMDS lines). Personally I would have preferred a DVI connector instead of the DP, because more people can potentially use that.

For HDMI Audio, NVIDIA requires you to feed an external audio source, for example from your motherboard's on-board audio, to the card via SPDIF cable. AMD on the other hand has integrated a sound device inside their GPUs which is the easier solution for most users. Also AMD's integrated sound device has been upgraded to support HDMI 1.3a which includes Dolby TrueHD, DTS-HD, AC-3, DTS and up to 7.1 channel audio with 192 kHz / 24-bit.


CrossFire configurations are supported to improve performance even further.


Here are the front and the back of the card, high-res versions are also available (front, back). If you choose to use these images for voltmods etc, please include a link back to this site or let us post your article.

A Closer Look

ASUS is one of the first companies to adapt the Direct-Touch heatpipe system on a VGA cooler. You can see the two copper heatpipes that sit right above the GPU core. They have been milled flat to make optimum contact with the die.


After removing the main heatsink you are still left with one heatsink sitting on the voltage regulator circuitry.


The VRM heatsink is just a simple metal heatsink - plenty for the cooling requirements of the PWM phases.


ASUS has decided to put one six-pin and one eight-pin connector on their card. In our testing we saw a maximum power draw of 171W, which justifies this configuration.


The GDDR5 memory chips are made by Samsung, and carry the model number K4G10325FE-HC04. They are specified to run at 2500 MHz (5000 MHz GDDR5 effective).


The GPU voltage is managed by a uP6208 voltage controller, which does support I2C software voltage control with up to ~1.8V. The bundled ASUS SmartDoctor utility supports software voltage control up to 1.35V. Our latest GPU-Z 0.3.9 can also monitor this voltage regulator, but not as detailed as Volterra controllers for example.


This is AMD's Cypress GPU, it comes with a whopping 2154 million transistors and is produced on a 40 nm process at TSMC Taiwan. The Cypress die size is 334 mm².