I need some advice on what memory speed would be best for this motherboard/CPU configuration, http://www.newegg.com/Product/Product.aspx?Item=N82E168... and a Phenom II 965 BE. What confuses me is that some people say AM3 chips can only use DDR3 1333 (10666) speed memory...If I was to buy DDR3 1600 (12800) it would automatically clock it to 1333 correct?
IF your FSB is set to the default speed of 200 then yes but if you go into the BIOS and change the Memory clock to 8.00 instead of the default of 6.66 that will increase it to 1600 (ie 200x6.66 = 1333 and 200x8.0=1600) or if the MOBO does not support x8 then you can adjust the FSB to 240 and leave the multiplier at 6.66 you'll have the memory clocked to 1598 but that will also OC the CPU so you may need to change the settings for the CPU, NB, etc. since they also rely on the FSB (so much easier to adjust the RAM if the MOBO also supports the higher Memory clock multiples !!)
EDIT : Since the MOBO says it supports DDR3 1800 it should have multipliers up to X9 in the Bios !!
IF you use the memory multiplier it will not effect anything else and since the RAM is rated at that speed it should run fine at that speed (as long as you make sure the timings and Voltage are set correctly also ) - IF on the other hand you adjust the FSB then it also effects the CPU,NB, SB timings so could adversely effect them (though usually a 40MHZ. increase to the FSB is within the limits of most chips) but could cause some instability (until you adjusted some of the other multipliers) - so best to use the memory multiplier if available (since the RAM you bought is suppose to run stable at those speeds)