Phenom ganged and unganged modes

[Quintero]

So is there any difference on 780X what memory slots to use for "dual channel" ?

We'll probably see different solutions, just like with AM2 boards. Either way it shouldn't be chipset dependant.

On some boards, slot 1 and 2 constitute one channel, a design which favors scalability with four DIMMs rather than two. That's because the strobe mismatch between each slot within each channel would be smaller. The strobe delays are set on a channel basis, which means that each slot cannot be configured independently (each pair must share the same settings). Trace lengths and routing mismatches affect the strobe delays, and the smaller the distance between the slots that are sharing the same timings, the smaller the actual delay differences between the slots.

When using two sticks in dualchannel, the tables turn. Two sticks would normally scale a little bit higher on a board where slot 1 and 2 connect to different channels. Shorter traces mean reduced capacitive loading and possibly lower delays (like Max Async Latency), so with two slots populated it would normally be best to use the slots that are closest to the CPU..