System memory bandwidth and crunching speed

How much impact does RAM bandwidth have on crunching speed in SETI@Home?

Lets say, a PC has an Intel E2180 (Pentium Dual Core) CPU. How much performance difference will there be in using single channel DDR2 RAM and dual channel DDR2 RAM?

Im not entirely sure about that particular setup, but I definitely know going dual channel on DDR1 on my AMD system (and 1T timing) improved crunching time by at least a few minutes - and in these forums, minutes shaved off = more crunching done in the long run

Isn't switching from single to dual channel a little more than just a bandwidth change? I always thought dual channel and 1T timings were just as much a RAM latency thing as it is bandwidth. So if you're talking 1 stick v 2 sticks of RAM I'd say that's a relevant change because of the decreased latency - but I can't put any numbers to it ...