New System. Which is better Vista 32 or 64bit

Hi, Just built a new system for my FS9.
The specs are as follows:
Intel Core 2 quad 9550
Asus Q5 mainboard
8 gb of ram(only shows 3.5gb in 32bit)
Asus GTX 260 gpu
Vista Ultimate 32 bit.
Runs ok with sliders to the right but does not recognise the full amount of ram.
Could anyone advise whether to switch to 64bit.
Many thanks
Mark
The specs are as follows:
Intel Core 2 quad 9550
Asus Q5 mainboard
8 gb of ram(only shows 3.5gb in 32bit)
Asus GTX 260 gpu
Vista Ultimate 32 bit.
Runs ok with sliders to the right but does not recognise the full amount of ram.
Could anyone advise whether to switch to 64bit.
Many thanks
Mark
