Phenom II x4 955 BE & DDR3-1600

It should just automatically underclock itself to the correct speed, which I'm guessing is 1333

Hmmm...looks as though there's no point going for the 1600 then.

The motherboard supports up to 2000MHz RAM so the 1600MHz should be fine regardless of the processor. I think 1600 & 2000MHz RAM is technically not supported by anyone or thing as this setting is technically overclocked and not a stock setting but as long as the motherboard is OK with it, it should be fine. You may have to set the speed & latencies manually though (I did with my 1333MHz RAM as the motherboard underclocked it to 1066MHz as default).

Thanks, Simon12. On that basis I think I'll go for the 1600 after all. It sounds as though the worst that can happen is that I'll spend more on RAM than I need to.

Agree with simon12. I've have that processor you're asking about, the 955 BE and run it with 1600 MHz ram. Using it with the m4a785td-v evo and it works fine, the motherboard box actually says OC 1800+ so it encourages you to OC. As simon said, 1600 is an OC'ed rate so no one will support it. Legalities and stuff.

Thanks everyone, I think that wraps it up.

(I'd mark this as an answered question if I hadn't mistakenly started it as a discussion.)