Originally posted by messy:

i dont know what that mean. but ill keep this in mind

As far as i know XMP is used to overclock RAM - which can lead to instability and many other problems. So if the game has CTD while using it and none afterwards it obviously wasnt stable.

I would be very carefull in general with overclocking - thing is - if you really need extra power overlocking most of the time is probably a bad idea (heat problems and limits of overclocking, warranty issues, stability etc.) - and if you dont need it its also not that great (warranty problems, stability, heat etc.)
There is also another big problem - many people overclock without actually knowing what they are doing - most of the times its rather "easy" to overclock because you can do it in a lot of ways (some programs do a lot of stuff automatically) - but many people often dont realize the other stuff they changed in the background (a lot of settings can affect multiple components) that can actually lead to big problems (and many also fail to have proper cooling and stability tests).

After doing some google searchs - it seems that using XMP profiles actually voids warranty. (to be honest i didnt know that either until now)