ATI x16 vs x8 Performance

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A couple of weeks back we looked at the performance of the nForce x16 chipset by plugging a couple of 7800GTX cards in SLI mode and finding out how much extra performance we could gain by having two dedicated PCI-E x16 lanes instead of one that?s split into two X8 lanes. The results were disappointing with only one game, Quake4, showing any performance gains.

Now with ATI?s Xpress 3200 Northbridge officially launched, we figured its only fair to put ATI to the same test and thus today, we will show the performance difference between two X1900XT cards under the older ATI RD480 chipset which has two PCI-E x8 lanes and the newer ATI Xpress3200 with two dedicated PCI-E x16 lanes.

Before we get to the testbed, we would like to point out that the % difference in the upcoming pages is between an x8 and an x16 board on the same manufacturers chipset. For example, if you see a +2% on the ATI X3200, that means that its 2% faster than the RD480. Similarly, a -1% on an nForce4 x16 would mean that its 1% slower than the nForce4 SLI. It'll probably be clearer once you see the graphs in the upcoming pages. Let?s take a loot at the testbed.

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