Can I clean install Vista Ultimate X64 SP1 with 4GB RAM remain untouched?

Can I clean install Vista Ultimate X64 (SP1 built in) with 4GB RAM
remain untouched and fully address/use whole 4GB RAM after installation

Or I've to remove 2GB RAM for the installation...and put them back till
it finished and reboot?

please advice,thanks again~~~


Intel® Core? 2 Extreme QX6850 (8MB,3.67GHz Factory overclocked)
Windows Vista® Home Premium SP1(Vista Ultimate 64bit SP1 pending)
nVidia GeForce 8800 GTX 768MB
500GB - Seagate 7200RPM, SATA 3.0Gb/s, 16MB Cache
4GB Dual Channel DDR2 SDRAM at 800MHz - 4 DIMMs
Sound Blaster® X-Fi? XtremeGamer (D) Sound Card
Logitech Z-5500 THX-Certified 505-Watt 5.1 Digital Surround Sound
Speaker System
Logitech® MX? Revolution Cordless Laser Mouse
Dell Ultrasharp? 2707WFP LCD