you want to keep the same processor but change the mb and RAM?
This is nuts and a waste of money. It would not make your computer run faster , nor produce higher frame rates . There is no performance advantage in using DDR3 .
There is a small gain to be had from upgrading processor, motherboard and RAM and graphics card to the latest Intel or AMD hardware , but before you spend the money it would be helpful if you told us what resolution you play at and what your operating system is
My x38 board supports DDR2 and DDR3. The only way I could see doing this is if you want to upgrade your machine and want to buy the RAM now seeing as its cheap. (8GBs for $50.) If you have everything you needed then go for it. But if you'll have to buy a new board and ram, then it makes less sense. Unless your going to get the CPU to go with the new board. But then your upgrading, and not just buying new ram.
you run a proc with the core2 duo architecture...that particular proc was compatible with DDR 2 and 3 but here's the fun part. core 2's actually were more stable,faster and reliable with DDR2 settings. You either need a really mid-high end DDR3 LGA 775 package board to get that 9650 to its bleeding edge via overclocking which at this point of time is "a-waste-of-money+effort" since for the same price of LGA775 DDR3 mobo+DDR 3 ram (where the mobo alone will cost you 2/3 rd's) ... you could get an intel SB proc/mobo/ram combo - and you'll have a system thas better than currently spec'd.
* I'd say live with what you have until it gives up the ghost or if someone in your circle gives a kick@$$ DDR3 LGA775 mobo for overclocking