Review Index:

AMD Radeon HD 6990 4GB Dual GPU Cayman Graphics Card

Author: Ryan Shrout
Manufacturer: AMD

The Radeon HD 6990 Graphics Card

Now that we have gone over all the technology that makes the new AMD Radeon HD 6990 tick, let's take a quick look at the card itself before we dive in the likely-game-winning benchmarks.

From this angle the HD 6990 looks like any other recent AMD graphics card with the signature red/black color combination and a very similar stylized look to the HD 6800 and HD 6900 series that came before it.  The fan is placed in the center of the PCB, directly over the power regulation components and right between the two Cayman GPUs that power it.  AMD claims that this will give the card better cooling properties as both GPUs see the same amount of air flow and the same temperature of as well.  Obviously half of that air will vent BACK into the case though since only the air going over the forward GPU will be exhausted to the outside. 

Flipping the card over shows us the dual GPU heatsink brackets and also gives you an indication of just how long this card is when you see the size of the x16 PCI Express connection. 

The display connections are shown here - four miniDP connections and a single dual-link DVI output as we discussed on the previous page. 

This card uses a LOT of power and as such it requires a pair of 8-pin power connections to get the job done.  Not only that, but if you are planning on unlocking the card to its overclocked settings and perhaps even going further than the 880 MHz speeds that offers, then you'll need a very good power supply.  Drawing more power than the PCI Express specification actually permits means that any components that are on the edge of compliance will be your failure points so be ready to upgrade to that 1200 watt unit you have been drooling over.


On the front end of the card we find a single CrossFire connector that will allow you to connect the HD 6990 to another single or dual-GPU graphics card in the Cayman family.  Yes, that does mean you can connect another HD 6990 or an HD 6970 if you happen to already have one of those for a 3-GPU configuration.  The small bit of padding there is likely just installed for shipping and side-by-side card configurations; you know, a little extra cushion for the pushin'.

As far as the actual length is concerned, the new Radeon HD 6990 4GB card is the same 12-in PCB size used on the previous dual-GPU card, the Radeon HD 5970.  Yes, that is still HUGE but we are glad it didn't get any more 

The HD 6990 doesn't just use your standard heatsink though and instead combines a new TIM compound with dual vapor chambers to keep the Cayman parts running at their best.


Each GPU has its own vapor chamber of the same design used in the single GPU cards to facilitate the best cooling while keeping fan noise down.  The newest addition to the equation is a "phase change TIM" (thermal interface material) that rests between the GPU itself and the vapor chamber that AMD claims sees an 8% better thermal performance compared to what they have used previously.  What this means for extreme cooling fans is that once you take this cooler apart you will not be able to simply put it back together with a new coating of your favorite thermal paste and have it operate with the same performance levels. 

This was such an important issue for AMD that they made note of it in our first meeting, which they have never done before.  I was told to be sure I do my noise and temperature testing BEFORE I wanted to take the thing apart and that even then for future testing they would recommend it be taken apart at all.  Instead, they provided us with these photos of the internals. 

Now let's getting into our testing methodology and graphics card comparisons and on to some real-world testing!

February 19, 2012 | 04:30 AM - Posted by Sajid Bashir Shaikh (not verified)


I am Sajid from India near Navi Mumbai City
I want to buy Graphics Card

I have Desktop PC of Intel DG965WH Motherboard + intel G965 Chip set Family Processor

and also I have Monitor from of model no. - e951F

so plaz check proper Graphics card or entry Level with 1 GB

i have DVI connection with deffault connection

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