In 3dMark06, Canyon Flight (test 3) is really the only test you'll find to be nearly 100% GPU-bound (i.e. mostly affected by the GPU clock, and it goes strongly upward when using SLI).
The first two GPU tests, when you're using a GPU as nice as a GTX260 (while they'll react slightly to SLI or GPU OC's) are more strongly influenced by your CPU's Clock Speed (not by the # of cores, though). They are, as we say, CPU-bottlenecked tests ... at least, when run at the 'stock' benching settings, with a nice video card, they tend to be...
The CPU test scores, of course, are influenced by # of CPU cores, the clock speeds, the IPC (efficiency) of the processor, and to a small extent, your rig's memory bandwidth.
The fourth test is a bit of a mixed bag, typically you can increase your score slightly by increasing your gpu or your cpu clocks, it reacts to each about the same way ...