New Gaming System Suggestions

[Superthinker]

Hi, I am a first time builder and am considering the combination:

MOBO: Gigabyte GA-MA770-UD3 Motherboard rev.2
CPU: AMD Phenom X4 940
RAM: 4GB Kingston Hyper-X 1066MHz DDR2 Dual Channel Memory Kit (2*2GB)
VIDEO: XFX Radeon HD 4890 HD-489A-ZDFC
HD: 500GB Western Digital Caviar Black 3.5" Hard Disk Drive 32m cache WD5001AALS
OD: LG GH22NS50 22x DVDRW
CASE: Antec Sonata III Midi Tower (EarthWatts 500W PSU inc.)
MON: BenQ G2220HD

On budget of 800GBP.

The major uses of the computer would be gaming and scientific programming/calculation. I prefer to have a quiet working environment and do not intend to overclock or update the system.

Here I have several doubts:
1. Will the cheap mobo introduce any bottle neck to other hardwares?
2. Is the 500W PSU good enough for the system?
3. Will these CPU and video card be too loud in idle mode? Will I need an aftermarket cooler?

Many thanks!

[elex13]

u should go for ddr3 ram supported mobo which is very hlpful as future technology also.go for gigabyte ga-ep43t-ud3l the best mobo everby gigabyte in ddr3rram segment...and in price rs 7400 only.