The ATI Radeon HD 3870 X2 video card (known internally as the R680) was first seen by the world right here on Legit Reviews a few months ago and was again spotted at CES 2008, where the the retail card was seen. Everyone knew that the launch was close, but today is the day that the card is officially announced. The ATI Radeon HD 3870 X2 is a single-board with multiple-GPUs on it, which is why the card is so interesting. ATI took two RV670 cores (Radeon HD 3870) and put them on the same PCB with the same amount of memory with the bridge chip already on the video card that enabled CrossFire automatically. The result is a graphics card that has two RV670 cores with 1GB of GDDR3 memory at a price point of $449, which puts it in competition with the GeForce 8800 GTX and the GeForce 8800 Ultra graphics cards by NVIDIA.
The ATI Radeon HD 3870 X2 graphics card delivers up to twice the Gigaflops per watt of previous generations of high-end AMD GPUs as it is basically two ATI Radeon HD 3870 cores on one card. This means that the ATI Radeon HD 3870 X2 video card should deliver twice as much performance and all the specifications remain the same. It should be noted that the Radeon HD 3870 X2 has enough math processing muscle to break the 1 TeraFLOPS mark!
Just looking at the video card one can tell just how beefy the cooling system is and see that it must consume some power as it has two power connectors located along the top edge of the card. The ATI Radeon HD 3870 X2 graphics card requires a minimum 500W or greater system power supply for single card operation. Since the board power usage is less than 225W only the two 2×3 PCI Express power connectors are requierd in normal operation. The 2×4 PCI Express power connector may be needed for overclocking, so keep this in mind if you plan on overclocking. For running a pair in CrossFireX it is unknown what the requirements will be as ATI has not made this information public since the CrossFireX drivers are still in development.
The core frequency on the R680 is higher than that on an RV670, which is a shocking move. The ATI Radeon HD 3870 has a core clock of 775 MHz while the ATI Radeon HD 3870 X2 has been increased up to 825 MHz. This might have been down as the memory clock was decreased from 2.25GHz GDDR4 to 1.8GHz GDDR3. (note the above slide is dated and that the memory clock frequencies have changed) This slide does point out that the ATI Radeon HD 3870 X2’s cooling fan operates at 36dBA, which is just slighting higher than the 34dBA seen on the Radeon HD 3870. The boards peak power usage is also 91W higher than the Radeon HD 3870 at 196W under full load. Having two RV670 cores on one board doubles many things like the frame buffer size and the math processing power, but the power consumption does not double.
The single CrossFireX interconnect can be seen above and is for when two of these are paired together. Since it has just one CrossFireX interconnect just two of the cards can be run together, so don’t think you can buy four Radeon HD 3870 X2 graphic cards for CrossFireX with 8 GPUs! The back of the card doesn’t have too much interesting to talk about, so lets take off the cooler!