Will Upgrading my CPU/Ram give me better open GL FPS ?

I want to upgrade my CPU from a AMD 64x2 Dual Core to a AMD Phenom II x4 920 Quad Core and update my memory from 4 sticks =3070MB at 667mhz. to
2 Sticks=4GB DDR2 800mhz.
My question is. First, will it work ? and when gaming, will the upgrades boost
my open GL FPS ?

My Computer is as of 2/21/11

Motherboard is: ASUS, M2N32-SLI, Deluxe
AMD Socket, AM2+/AM2
NVIDIA nforce 590 SLI
2xPCI-E x16 Slot,Nvidia SLI Support, At Fullx16x16 Speed
Dual Channel DDR2 800/667/533 Memory/Ram

CPU/Prossesor is: AMD Athlon (tm) 64x2 Dual Core Processor 6400+
Want to upgrade to : AMD HDX920XCJ4DGI Phenom II X4 920 Quad Core Processor

Ram/Memory is:
Total Memory is : 3070MB
4 sticks total
2 sticks are: 1024MB,667mhz(speed) 64bit
2 sticks are: 512MB,667mhz(speed) 64bit

Want to upgrade to :
2 sticks total
2 Crucial 2048 PC6400 Memory and Ultra TherMax T5 Aluminum Memory Cooler Bundle.
2GB,DDR2 800MHz, DIMM, Contains Heatpipes

2 Video Card's running in SLI
NVIDIA Geforce 9800 GT 1024MB GDDR3 PCI-E 2.0
NVIDIA Geforce 9800 GT 1024MB GDDR3 PCI-E 2.0