AMD 6800 Series Reviewccokeman , RHKCommander959 - October 21, 2010
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In addition to the offering from Sapphire we have two cards to look at from XFX. The HD 6870 and their non-reference version of the HD 6850 of which they have two different designs, One that is heat pipe equipped and one that is Vapor Chamber equipped. The one we will be looking at today is the heat pipe equipped card. The packaging of the XFX HD 68XX cards are almost identical with the main difference being the name listed on the front. This graphic is mirrored through to the graphics card inside. The design is very minimalist with little information on the front of each box. Highlights include the mention of XFX 5 star support that should be helpful if the unthinkable happens. The rear panel contains the list of the HD 6800 series feature set that includes DX 11 support, Eyefinity technology, Display Port 1.2, HDMI 1.4a, Crossfire Support, Enhanced UVD 3 decoder and more.
The box internals are incredibly similar so I am only going to show one package. The internal packaging is black with the XFX logo with the Play Hard slogan underneath and the XFX web link to the right. Flipping open the lid you get a tray that houses the extent of the accessory bundle. Underneath the tray is where you will find the video card which packaged securely in a cardboard cocoon. You will notice that the HD 6850 takes up significantly less room in the box than the HD 6870.
The accessory bundle is actually kind of slim with an install guide, AMD GPU guide, driver disk, an ad for XFX's own brand of PSU, a crossfire bridge connection and a door tag that lets people know you are getting your Frag on!
The HD 6870 from XFX mirrors the reference design in form and function. This card is built on the Bart's family of GPU processors from AMD. The HD 6870 comes in at 10.5 inches in length and is meant to be used in a PCIe 2.1, 16x slot on your motherboard. The graphic has carried over from the packaging and offers some eye appeal. A quick look at the specs of the 6870 shows the card to have 1120 Stream processors, 56 texture units, 32 ROPs and 1GB of GDDR5 memory running through a 256bit bus. The smaller of the pair (but no less capable) is the custom HD 6850. It is slightly shorter than the reference card but comes packed with enhancements such as a dual heat pipe cooling solution, Solid capacitors, DR Mosfets, Programmable PWM IC for stable voltage and built-in thermal protection and a two ounce copper layer in the PCB. All of these enhancements should help to increase stability and extend the life of the card.
Both of these cards from XFX use a custom cut backplate that features the XFX logo cut into the exhaust port for increased cooling airflow. The connectivity options differ slightly between the two cards. The HD 6870 uses two Mini Display port 1.2 ports, a single HDMI 1.4a port, and two DVI ports, one of which is single link. However, if you need two dual link ports you can always pick up a Display Port to DVI adaptor for those situations. The HD 6850 From XFX has gone astray from the reference version for connectivity with a single full size Display Port 1.2 port a single HDMI 1.4a port and a pair of DVI ports. The back end of the 6870 is sealed shut so all of the airflow must come through the front of the card. A good thing in this case since the power circuits are moved forward on this card. The rear of the HD 6850 is ventilated much better with holes in the shroud for air intake or exhaust for the heat pipe based cooling solution. Power is supplied to the HD 6850 on the end of the PCB via a single 6 pin PCIe power connection while the reference based HD 6870 has two 6 pin PCIe connections on the spine of the PCB. Power consumption is rated at 151 watts on the 6870 and 127 watts on the 6850 with both cards dropping down below 20 watts at idle at 19 watts.
Both cards only support a total of two cards in Crossfire, Something normally seen on AMD's mid-ranged product lineup. This should mean that further up the stack with Cayman we should see CrossfireX again.
The cooling solutions used on these cards vary significantly as one is based on the reference design and one is an in-house build. The reference cooling solution on the HD 6870 is a three piece design that has a plastic shroud, an aluminum base for cooling the motherboard components such as the memory and power control circuitry and a heat pipe equipped cooler for the GPU. The air blows through the shroud and through the heatsinks to exhaust the thermal load outside the chassis. The aluminum base has a set of fins on it in the airstream to help cool the mainboard components more effectively. The solution used on the XFX HD 6850 is a dual heatpipe design that has an 80mm sleeve bearing fan that pushes around 52 CFM worth of airflow through the shroud. The dual heat pipes attach to the copper and aluminum base and form a circle around the fan to most effectively use the airflow to keep the mosfet cooler from running too warm. The fan on the reference cooler leaves a lot to be desired. How so? While it does allow the 6870 to operate relatively cool, it does so with a tremendous noise penalty. More so than the cards of the past - this is a screamer. Not just loud, but "nails on a chalkboard" loud when run to 100% of its speed potential. On the other hand, the fan on the HD 6850 was audible but was nowhere near what the reference design had to offer.
Of course what good is a shot of the heat sinks if you don't know how they are mounted? Each card is shown with the heat sink removed as a frame of reference. You can see how the PCBs are much different but both share the power circuitry towards the front of the card. Here you can see the solid caps and covered chokes.
Last but not least, we can look at this pair of Bart's GPU cores. Both are built using a 40nm process and differ in the amount of Stream processors (1120 vs. 960), the amount of texture units (56 vs. 48), each has 32 ROP units and 1GB of GDDR5 memory on board. Clock speeds for the HD 6870 come in at 900MHz on the core and 1050MHz on the 1GB of memory. The HD 6850 is clocked at 775MHz on the core and 1000MHz on the memory. Hynix memory is used on both cards and carries part number H5G01H24AFR-T2C stamped on the IC's. They are rated for 1250MHz operation.
One more card to look at from Power Color and then we can get onto the testing.