ASUS EAH6850 DirectCU OC Edition Reviewccokeman - November 25, 2010
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The first look you get of the EAH6850 DirectCU from ASUS tells you it's not simply a reference design video card with a sticker slapped on to show who holds the warranty liabilities. Nope, this is an ASUS design that is a step away from the reference mold in both scale and configuration. First off, the EAH6850 comes in at just under ten inches in length and uses a large ASUS designed heat sink equipped with two 8mm heat pipes that make direct contact with the GPU core. The other item that stands out is the support bracket that runs down the spine of the card. This addition helps keep the card from from bending when larger heat sinks (such as the one this card is equipped with) are installed preventing possible stress cracks and broken circuit traces. Couple that with a jet black PCB and you have a card that looks great and has an industrial feel to it that should integrate into many of the industrial looking cases that are popular now such as the HAF932 from Cooler Master.
The EAH6850 DirectCU deviates from the standard reference design connectivity by using a single full size DisplayPort 1.2 connection, a single HDMI 1.4a port, a single Dual Link capable DVI port and a Single Link DVI connection that can be used for a VGA connection with the supplied adapter. Even with the deviation from the reference design connectivity, you have the ability to run Eyefinity from just this single card using the correct set of adapters. The back end of the card is wide open allowing the heat sink to breathe and exhaust the hot air out into the chassis. Not the ideal solution, but with proper chassis airflow, increased case component temperatures from card can can be overcome.
The less than $200 price point is not the realm of the high-end enthusiast so AMD chose to only allow a two card configuration on the HD 6800 series. This is evident by the use of only a single Crossfire bridge connection on the EAH6850 DirectCU. That should not be an issue though as the performance scaling is pretty incredible now when using these cards in Crossfire mode. Performance wise, it should come in just under or equal to the HD 5970 based on its performance against the HD 5850. For additional power, the EAH6850 is equipped with a single six pin PCIe connection.
Across the spine of the card is a stiffening bracket that helps keep the card from getting a bad case of the bends. This means you can be sure that a larger heat sink will not cause issues with stress cracking of the PCB. Coupled with ASUS GPU guard technology, should mean that whatever you use for a cooling solution (from the stock supplied cooler to some of the the totally insane coolers out on the market) you should be fine and not have to worry about the card. ASUS has used its EMI shield technology to make sure that any stray EMI emissions do not impact the clarity of the signal being output to the display device. The technology used by ASUS is said to reduce EMI emission levels by 66%.
By pulling off the heat sink we can take a look at the card and inspect the heat sink itself. One thing I noticed right away after looking at several other HD 6850 video cards was the lack of additional cooling on the power circuitry. I have to wonder if this will impact the clock speeds I am ultimately able to achieve. I also have to wonder if this is an oversight and this sample was a Monday or Friday edition being that every one of the HD 6850 video cards I have tested had this area cooled. What you do notice is that the heat sink is mounted far enough from the I/O panel that the thermal energy dissipated by the DirectCU heat sink will be dispersed into the chassis. The TIM used on the card is a thermal pad that is more than difficult to remove but does adequately seal the gap between the heat sink base and the GPU core. Most people will never pull this cooling solution off but this is what you get. When asked why they use this kind of solution it comes down to getting the right amount of material in place versus having to much TIM applied. A prime example of where more is not really a better idea!
The heat sink used on the EAH6850 DirectCU is a Heat pipe Direct Contact design. This technology has proven itself time and again when implemented and built properly. By this I mean that the heat pipes are level with the aluminum supporting structure not sitting below the level of the structure as is almost always the case. The base appears to be flat on this implementation with a good solid contact patch. The two 8mm copper heat pipes as well as the aluminum base carry the thermal load up to the fin array to be dispersed by the airflow from the fan. While the heat sink overall looks fairly stout you really only have two small fin arrays that will be dissipating most of the thermal load.
The fan used is a 75MM PWM fan that blows down through the heat sink. Flipping it over I was expecting to find some information on the fan but was greeted with a blank slate. When ramped up it is audible but not what I would consider a banshee type wail but a smooth hum. A nice improvement over the reference blower style fans.
The EAH6850 is built using the Barts core GPU from AMD. This 40nm revision of the Cypress architecture is 255mm² in size and contains 1.7 billion transistors so as an engineering exercise when you have a smaller die you have a more efficient die that gives almost similar performance to its older relatives, the HD 5800 series. The Barts core used on the EAH6850 houses 960 streaming multiprocessors. 48 texture units, 32 ROP units and 1GB of GDDR5 memory running through a 256bit memory interface. The GDDR5 1250MHz rated memory used on this card comes from Hynix and carries part number H5G01H24AFR-T2C. ASUS uses their GPU Guard technology to help increase structural rigidity of their video cards from 211 to 238% over their competitor's designs. One of the elements of this technology is evident by looking at the corners of the GPU. They use a process that injects glue under the corners of the GPU to stiffen it so that you do not crack it with the loads of an aftermarket cooler.
Now that the EAH6850 has been dissected and you know about the card, it's time to see how this card performs with its higher than stock clock speeds and if the DirectCU cooling solution can carry the load.