Which one

They are both good coolers and can handle oc'ing.
So go with the Titan if weight is a concern.

weight isnt too much a concern but if they provide similar cooling and one is lighter it is better for the motherboard isnt it?..................

weight shouldn't be too much of a concern ( as long as you are not shipping ) I have the Noctua D-14 weighs 900 grams ( 1.9 lbs ) I have no issues.. the backplate redistrbutes the weight and pressure to more surface area than the stock heatsink and board manufacturers build them to allow some flex

Neither, for an extra 5 dollars you could get the Spire TherMax Eclipse II that actually comes with two fans. Unlike the Prolimatech Megahalems. Also, http://www.frostytech.com/articleview.cfm?articleid=252...
According to those temps from frostytech, Spire beats both the fenrir and megahalems. A place you could buy it is here, http://www.coolerguys.com/840556091646.html, there not as big as newegg but newegg doesn't sell spire. Plus that place is local for me soo... That's why. Too bad they sold out like yesterday. Aha,