Phenom processors had 3 different tdp, it stands for Thermal Design Power which is the amount of watts a processor needs to perform its operation (at least that's what I understands):
Phenom 9550 and 9650 is 95W TDP
Older Phenom 9750 and Phenom 9850 are both 125W TDP
AMD has released a newer Phenom 9750 that has 95W TDP, you can search using google for tell whether your proc is 95W TDP
Bear in mind that amd motherboards with 780/770 chipsets does not support 125W Phenoms, but there are cases such as Asrock motherboards that worked.
Boards with amd 770 or 790 chipsets may need to flash bios in order to support newer Phenoms (the one that has xx50 as model number) and also Phenom X3. I think you can find motherboard bios from the official site, they should has listed new features added in the new bios
Usually flashing bios requires diskette but some motherboards like Gigabyte provide Q-Flash that allows bios to be flashed from usb thumbdrive.