A Closer Look

Sapphire's heatsink assembly is quite big and consists of two independent heatsinks that look a bit like CPU coolers. Each GPU controls its own fan speed depending on its own temperature. The heatsinks both have a small copper base where contact is made with the hot GPU to transport heat away more efficiently. Due to the cooler design hot air will not be exhaust out of the case.


You may combine two of these cards for even more performance in CrossFireX. You can also combine this card with a single HD 4850 (or HD 4870) card for triple CrossFire.


The card has one six-pin and one eight-pin power connector. Both are required for operation.


The GDDR3 memory chips are made by Samsung and carry the model number K4J10324QD-HJ1A. With a latency of 1.0 ns, they should be good for at least 1000 MHz.


Between the two GPUs sits the PCI-Express bridge chip which adds a fast interconnect between both GPUs to exchange data. The heatsink is epoxied on permanently. Usually I still try, but in this case the failure rate feels like 100% and breaking the card just to see the bridge chip doesn't seem to be worth it. Based on the readings in GPU-Z we can see that the bridge is a PCI-Express 2.0 bridge just like on the HD 4870 X2.


Two AMD RV770 GPUs are working together on the Radeon HD 4850 X2. The GPU has a die size of 256 mm², is made in a 55 nm process and sports 956 million transistors.