Overclocking and RAM speed query

[frogonastring]

Hello, clever people!

I've just upgraded the RAM on my ageing system from 8GB of DDR Corsair XMS3 1333mhz RAM (4 lots of 2GB) with some Kingston HyperX Savage 16GB - 4 sticks of 4GB, 2400MHz. (This stuff: http://www.kingston.com/dataSheets/HX324C11SR_4.pdf)

My system is an overclocked Core i7 860 - from 2.8GHz to 3.6GHz.

I've installed the RAM but under the default auto settings, it runs at 690mhz, so roughly the 1333Mhz that the old RAM was running at. If I enable XMP profile 1 (2400) it seems to drop the overclock and reduce the CPU speed to somewhere like 192Mhz?! It bluescreened on startup, obviously. 
XMP profile 2 (2133) boots fine but it changes the overclock to roughly 3.0GHz.

I'll be honest, I don't know a lot about overclocking. I managed the 3.6GHz because I was working from knowing that the system could get there (it came overclocked but I had to reset it following a system failure)

Can anyone provide any guidance for how to keep the 3.6GHz overclock and have the RAM run closer to it's designed clock speed?

(Oh, and I've boosted the DDR voltage to 1.65v as requested by the data sheet)

Basically I'm just a bit out of my depth and any wisdom would be very gratefully received. Thanks!