There is NOTHING to re-install!!!
I did this even with WinXP. Just install the drivers as long as it is running and make then a WORKING backup.
But if I remember correctly Win 7 has drivers for RAID already. At least it did not ask me when I installed it. When you are finished with your RAID setup just restore your backup on the new RAID disks. The backup does not care that it is RAID now because the OS does not see that it is RAID. It just sees what the RAID controller reports - in my case 2 disks because of the 2 RAID areas. If you select only 1 area then you will see only 1 disk. In respect of partitions there is no difference to a non RAID setup. Just check that your BOOT disks for such tools (partitions/backup) will work. So you will not get a surprise when you really need them. It is not so much because of RAID but because of all the SATA drivers.
XHD is just an easier setup for RAID. I used the setup for the Intel Matrix and not XHD. It was easy too. I created 2 RAID areas - both 0. This keeps the defragmentation lower. In the OS they will show up as 2 disks. Just be aware that SMART will not work anymore for the RAID disks. So no temperature too. But it is not realy important.
Use the Intel Matrix. You have to switch it to RAID in the BIOS. But this does not create a RAID disk. You will be asked afterwards outside the BIOS if you want to setup RAID areas for disks. Look in the mbo manual for details. One question you have to answer is the stripe/strip size. Default is 128. At my system 64 worked best, 32 was not bad. You can see it as the smallest storage size. And as the size when RAID will kick in because the file is split to several disks if bigger. It depends on your system and your data. So it is hard to find the perfect value. If a file is the same size as the strip or smaller you will loose a bit performance compared to a non RAID setup because the RAID controller has to think. But you might not realize this because this time lag is extremely small.
When you create partitions you will be asked for cluster sizes. It is said that it is best to keep the cluster size the same size as the strip size. This will not be possible for the OS partition if you use a bigger strip size. Don't change the clusters there. Depending on the OS the system might not boot!!! But you can use this rule on other partitions - so 64 strip size (the physical size on the disk) will be 64 cluster size (the logical size for the OS).
You can mix on the Intel ports disks with RAID and with non RAID in AHCI. I have for instance 2 disks in RAID there and two disks for backups in non RAID - all on the Intel controller. No need to use the JMicron - but perhaps for the DVD drive if it has problems with AHCI and likes IDE more.
From my experience with RAID 0 - I NEVER would go back. It is almost twice the speed with 2 disks. The HDs are on my system the biggest bottleneck. And it is stable - I made endless tests even with switching off the power while writing. No problems at all.
Sure SSD are faster - but still too expensive. I am dreaming of SSDs in a RAID 0 setup already
