AMD Radeon HD 4870 X2 technology preview @ Elite Bastards

[JackW]

Anyone who has found themselves poring over the block diagram for an RV770 core will have noticed some die space used for a 'sideport connector'. If you ever wondered what it was for, now's your chance to find out. In addition to that PCI Express bridge, the sideport on each RV770 core can be directly connected to another RV770 GPU core for direct communication and data transfer between the two GPUs. Much like a PCI Express 2.0 16x link, this direct sideport connection offers up 5 GB/sec of bandwidth, given a total of 21.8 GB/sec of bandwidth across the entire board's interconnects compared to just 6.8GB per second found on the Radeon HD 3870 X2.

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