HIS Radeon HD3870 X2 1 GB

A Closer Look

ATI's cooler is huge and quite heavy. It is uses a complex base plate that cools more than just the GPU and memory. The black piece of metal is sitting on the back of the card and cools the memory chips which are located there.


As you can see only a single CrossFire connector is present. This means you can run two of these cards in a Quad CrossFire configuration called CrossFireX (once it's available). It will not be possible to run three or more cards for even more powerful combinations.


All this graphics power needs a lot of power. AMD has placed two VGA power connectors on the board - one six pin and one eight pin. Just like on the Radeon HD 2900 Series Overdrive will be disabled when only two six pin power connectors are present. What I like a lot is that the power connectors are rotated to face down. This will make sure that you don't need any additional space in your case for the power connector and cables. Since the cooler is dual slot there is some space left anyway for the plastic part of the connector and the cable can be easily bent to route it properly in small cases.


The GDDR3 memory chips are made by Samsung and carry the model number K4J52324QE-BJ1A. With 1.0 ns latency (= 1000 MHz) they should have some headroom left for overclocking.


This big chip that sits between both GPUs is the PLX Technology PEX 8547, a PCI-Express to PCI-Express bridge chip. It connect the second GPU to the PCI-Express bus on the motherboard and also creates a direct link between the two GPUs for the CrossFire data. The question you should be asking now is "But does it support PCI-Express 2.0?" No it does not. That's also the reason why AMD can not advertise the card as PCI-Express 2.0 compatible. Of course the card will work fine on any motherboard that has support for PCI-Express 2.0, but it will not run at the increased speeds available. In my opinion this has no negative effect on performance, just on marketing. Since PLX offers a similar chip called PEX 8647/8648 which has the same features as PEX8547 plus PCI-Express 2.0 I expect AMD to switch to the new chip very soon to add this feature to the card.


Each of the two GPUs is the ATI RV670 which is made in a 55nm process at TSMC. This combination is called R680 GPU even though it is two parts of silicon.