There's no reason that ram should give you problems overclocking. You could for example in theory have a massive 4.4 GHz overclock on your CPU with 200x22 settings and still run your RAM on the x6 multiplier (assuming your board offers a x6 - can't remember if mine does now). If your board only offers a x8 as the lowest mem multiplier, you'd have to limit your bclk to 166 to keep the RAM at 1333 (166x8), which in turn would limit your CPU overclock to 166x20 = 3.66 GHz.
Out of interest why are you more concerned about a RAM overclock than your CPU, or is the CPU sorted? And what software are you using to try and overclock? Better done in BIOS really.