DDR3 oc, what's a strapping?

[Azuse05]

My sigs a little dated (voltage is wrong for one thing) but last month I retired my 4x1gb ocz ddr2 for 2x2gb geil ddr3 - £32 for 1600mhz, couldn't resist but run it at 1333 since.

Anyway, I'd now like to restore my 3.6 oc (400x9) with this new ram but unlike the other settings there's 3, 4x multipliers for it with either 800, 1066 or 1333 strapping in the bios. Since My old ddr2 was run at stock (i.e. I have no clue ) could someone explain what these strapping are, which I should use and why?

 

[Azuse05]

Well it's 1600mhz memory, I've just had it under-clocked at 1333.

The outcome in the bios is the same for each one. If I bring the cpu to 3.6 (400x9) then the ram options are auto (pretty sure it's 800), 1066 and 1333. Auto bsod after post, 1333 bsod ~30 sec into windows. 1066 is stable.

I don't really understand this though. The bios says 1600mhz, as does sandra (2x800, 1.6ghz) but it's also listing them as ddr3 1600/ddr 1334 but aida lists them as ddr3 1333 (667mhz). So what speed are they running at?

Edit: Well after some prodding it seems, while the ram may well be capable, 1600mhz is simply pushing a p35 chip too far (couple errors now and then) so I've settled on 1280 (400x3.2) with timings tightened to 8-8-8-24 instead. Still miles better than the ddr2 it replaced