Asus Rampage Formula led question...

Hello!

Got all my parts in and everything is together.
I'm installing XP pro 32 bit and had a couple general bios and XP questions please....

System:
mobo: Asus Rampage Formula
cpu: Conroe 3.0 e6850
ram: OCZ Reaper 2x1gb 1200 (being initially recognized as dual channel 667)
video: ati 1900gt
psu: Siverstone DA800watt (top tier psu)
hdd: 2 x sata 500 gb 32mb cache Seagate 7200rpm drives
optical: 2 x lite on dvd burners
+ floppy
o/s : xp pro sp2
Case: THERMALTAKE ARMOR = monster

Current Temps:
CPU Temp 32c/89.5f
MB Temp 25c/77f
NB Temp 39c/102f
SB Temp 37.5c/99.5f
CPU Voltage = 1.32v

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Questions:
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->when installing xp, I don't have a raid disk made yet and the bios is recognizing my 2 x HDDs as Enhanced IDE. SHould I install XP, go into XP, create a RAID disk and then reinstall windows?

->Another question, is Raid 0 much faster than non Raided drives?
I have matching SEagate 32 mb Cache 7200 rpm 500gb drives, and I could RAID 0 them, but not sure if its a waste of 500 gb? I'm not worried about data loss, just speed.

->In the BIOS: PCI/PnP settings, Plug and Play O/S is set to [NO] by default (haven't installed an O/S yet). Once Windows XP 32 bit is installed, will this be set to [YES] or should I set it to yes or no?

->Also, I need a little bios advice, especially since its seeing my ram as dual channel but at 667 instead of 1200... I didn't expect it to see the RAM at 1200, but I was hoping it would default at 1066 or worst case scenario 800, but its seeing both gigs as 667.
The OCZ Reaper HPC's should be compatible according to Asus' QVL, the timings are said to be 5-5-5 @ 2.1v.

->what about my Conroe settings in the bios (not o.c. settings).
I'm looking at teh Advanced CPU Configuration screen:
CPU Ratio Setting: (auto)
C1E Support: (disabled)
CPU TM Function: (Auto)
Vanderpool Technology: (enabled)
Execute Disable Bit: (Enabled)
Max CPUID Vaule Limit (disabled)
Intel SpeedStep Tech: (enabled)
Do I want to turn off SpeedStep so it won't throttle down? Or should I keep it in case of heat issues?


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THANKS in advance for any assistance!!