Recently upgraded some pc parts, And bought an amd card ive never used one before therefore never known about amd overdrive.

Intel i5 650 clarkdale 3.2ghz
xfx 7850 DD 1gb
8 gb 4x2gb ddr3
Motherboard is the whatever was in it when it was originally shop bought (acer aspire x3950)
500W coolermaster lite psu

What i would like to know is.

1) is amd overdrive safe to use?

2)will there be any noticeable performance increase?

3)is it possible to screw my card over while changing things in amd overdrive?

Never overclocked anything before and dont want to damage my system for no reason.

Thanks for any help and suggestions.