ASUS speeds up Crossfire on P965

A few weeks ago a new ATI Catalyst driver enabled the usage of Crossfire setups on Intel P965 chipset based mainboards. Of course the Crossfire performance on P965 is lower than with 975X boards: with the 975X chipset it's possible to split the 16 PCI-Express lanes offered by the north bridge to two pairs of 8 lanes for both cards. With the P965 the PCI-Express lanes can't be devided and the second card has to be connected to just four PCI-Express lanes provided by the south bridge. Both the lower amount of lanes as well as the extra latency due to the connection between north en south bridge make Crossfire on P965 run more than 10% slower on P965 than on 975X.

A new ASUS technology called Cross Graphics Impeller (C.G.I.) speeds up the data transfers between north and south bridge, which increases the Crossfire performance on P965 boards. It's unclear how C.G.I. exactly works, but we expect that ASUS dynamically overclocks the bus between the two parts of the mainboard chipset. 

C.G.I. is with a new BIOS available for all ASUS P5B Deluxe and P5B Deluxe/WIFI-Ap mainboards. The benchmarks below are provided by ASUS and show the impact of C.G.I.

Tags: overclocking bios crossfire

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