Upgrade my processor


Oct 10, 2011
I have an Hp e9120y desktop. I have made many upgrades to computer , Upgraded power supply from 300w to 630w , Upgraded graphics to Geforce gtx 550 ti Amp . I also increased ram to 16 gig.
I want to upgrade my processor. My current processor is a AMD Phenom II X 4 910 , Operating speed: Up to 2.6 GHz
Number of cores: 4
Socket: AM3/AM2+
Bus speed: 4000 MHz HT3
Hp support gave me this information on upgrade , Socket type: AM3
TDP: 95 watt
Motherboard supports the following processor upgrades

AMD Phenom II X4 9xx/9xxe/8xx Quad-Core (Deneb)
AMD Phenom II X3 7xx/7xxe Triple-Core (Heka)
AMD Phenom II X2 5xx (Callisto)
AMD Athlon X4 6xx/6xxe (Propus)
AMD Athlon X3 4xx/4xxe (Rana)
AMD Athlon X2 2xx/2xxe (Regor)

My Motherboard is a M2N78-LA ( Violet 3) , Manufacturer: Pegatron
Form factor: Micro-ATX: 24.4 cm (9.6 inches) x 24.4 cm (9.6 inches)
Chipset: NVIDIA GeForce 9100
Memory sockets: 4 x DDR3
Front side bus speeds: 5200MT/s (5.2 GT/s)
Processor socket: AM3
Expansion Slots:

1 PCI Express x16 slot for graphics card
3 PCI Express x1 slots

I need advice before I buy. What is the best , fastest , processor , I can get to work on the motherboard.