Slow to START booting, help!

[kawininjazx]

I have a system I built for someone, here's the specs:
Core i7
8GB DDR3
Gigabyte P55A-UD4P
2 X ATI 5770
Creative XFI
Corsair 750
2 X Velociraptor 300gb RAID 1 (mirror)


Ok, I just did a fresh install of Win7 PRO x64. When I do a cold boot, as in the system is completely off, it sits at "Loading Operating System" for about 3-5 minutes then it starts booting and its real quick. If I reboot, it comes up right away. Any ideas on what can cause it to hang before booting?

BIOS have been updated, I pulled the video cards, sound card, DVD drives, and all but one stick of RAM, still does it. IDE + JMICRON are turned off in BIOS, boot is set to ONLY INTEL MIRROR array. I have no idea what to do, help? Ran chkdsk on Hard Drives, 0KB bad sectors.

 

[ksampanna]

Run a memtest on each of the RAMs

 

[insightdriver]

I agree with ksampanna.. try with only one gig of ram. boot. .it should boot fast. Try each stick alone. Then, try 4 gig. I suspect the bios is testing the memory. Assuming all the memory is good, did you try a fast boot that skips memory testing?