SpIk3y wrote:
if you are using a am2 cpu that uses an odd muliplier then yes it will underclock it. my x2 6000 used a multi of (200x15=3ghz) and it clocks the ram at 375 at stock speeds.
to get the ram to run at 400 I have to oc a little (215x15). the even multi's don't have this issue.
This was posted by a tech-wiz on the AMD forums when I asked why my RAM was not running at the proper speed.
AMD's have an integrated memory controller on the die, so the multiplier does affect the RAM speed. So when you increase the CPU frequency, the RAM speed goes up. This is why the OP should just overclock a little bit to boost the RAM to the right frequency.
Well I suppose since it's derived from the overall CPU frequency rather than the bus rate, you could have an issue. But surely it balances out ok, doesn't it? If not that's really crap design. It certainly doesn't impact the 939 or 754 CPUs which also have the memory controller on die - but that could be down to the lower 200MHz clock rate which would be easier to get accurate dividers for - lets have a look:
3GHz = 3000, using an integer divider we are limited to 7 or 8, which works out as either; 3000/7=428 or 3000/8=375, neither of these is what we want.
Whereas for DDR boards: 3000/15=200 - works perfectly.
I realised the AM2 design was a bit shoddy - I didn't realise they'd just shifted over their existing technology without modding it to fit the new memory requirements properly, that's shocking.