Still need to know the motherboard to see if it supports RAID via the chipset.
Windows can do software raid, no need for a controller as windows is the controller. 2008 supports 0, 1, and 5 only.
@OP, For RAID 10, you will need a hardware controller.
Windows Server 2008 includes an excellent and flexible implementation of RAID levels 0, 1, and 5 in software. It doesn't cover all the possibilities by any means, but it is certainly sufficient for some purposes. However, most serious servers should be using hardware RAID.
OP wants RAID 10, so Windows can't do it, right? It can only do one or the other, not both, right?
And IMHO, this says it all:
The overhead for software RAID is higher and there is more inherent risk.
Correct, as I stated earlier, windows only does 0, 1, and 5, thus needs a hardware controller for raid 10.
As for software raid being riskier, I'm not sure about that. The one nice thing about using windows raid is it's easy to migrate the array to another windows computer. This is also true if you have a raid card in your computer. A motherboard's onboard raid however can be difficult to migrate since different boards use different controllers.
As I understand it, there is some confusion about "Hardware RAID" vs. "Software RAID".
Almost always, true "Hardware RAID" is done by adding a RAID controller card into your computer, usually in a PCIe slot. This card has a number of key components. First, it has a group of HDD controllers and ports, all run by the card's other "smarts". It has a Processor chip that is dedicated to running the card, and most importantly to doing the computational work for the RAID tasks. It has some RAM used rather like a large buffer for its own tasks. It has a BIOS containing the software for doing its jobs. And it has support chips to tie all this together and communicate with your computer. In other words, it is itself a small dedicated microcomputer with a specific range of capabilities, but it is not a general-purpose microcomputer. Because of this, it can do almost all of the considerable work involved in managing a RAID system, so that your computer's main resources (CPU, RAM, HDD controllers, BIOS, etc.) do NOT have to be used for this work. Thus your main system is left free to work quickly on your tasks, while the RAID work is done by the Hardware RAID system. Obviously, when you choose a RAID card, you must be sure it can do what you want - has enough ports for HDD's, supports the type of RAID you need, includes utilities for maintenance and diagnostics of the RAID array, etc.
One factor to be considered in using RAID is that there is no set of "universal" ways to do RAID. Thus it is common that a set of data written on a set of HDD's in a RAID array by on particular RAID system cannot be read and understood correctly by a different RAID system. Now, there certainly are ways to avoid this problem. One of them is to use a true "Hardware RAID" system so that you can physically move the RAID card from one computer to another along with the HDD's of the array. Then there is no "other RAID system" involved. Of course, it is possible that the RAID card itself might fail. For that possibility, you need to choose from a card supplier in which you have confidence of their continued existence in the future so that you can buy from them a replacement card that is guaranteed by them to be able to handle your HDD's exactly as their original card did.
"Software RAID", on the other hand, is RAID done almost entirely by software, and what Windows in its various versions can do is a good example of that. It uses physical resources of your computer to do all the work (thus consuming processing time, of course) so it does not cost money for extra hardware. One huge advantage of this is that the software is completely able to operate on any machine that can run that OS, so moving your RAID array HDD's from one machine to another should work easily, as long as the software is kept the same. On the other hand, software sometimes has bugs or quirks and fails for this reason. Or in this case, the Windows version of RAID apparently does not do the type or RAID that OP wants to use.
The "confusion" I mention arises from the in-between RAID systems. Of these by far the most common is the RAID capabilities built into most modern mobos. They offer to do several types of RAID just by connecting HDD's to existing mobo ports and configuring the RAID array in BIOS and using a RAID management built-in application. Although some think of this as a hardware RAID system because there is no special software to install and run, in fact it is a Software RAID system. The software is simply included in the mobo's BIOS chip, and it uses the computer's hardware devices to do all the work. It may make use of a few extra capabilities of the HDD controller chip on the mobo, but it is still a Software RAID system. Its huge advantage is it is "free" - there is virtually no extra cost for this capability in the system. Its major disadvantage is in the portability question. If your mobo fails and must be replaced, you are now trying to use HDD's written by one RAID software system on a different one, and this often does not work. The only preventive solution I know of for this is in guarantees offered by a few mobo chipset makers. SOME of them guarantee that, as they develop and deploy future mobo chipsets, they will ensure that they all run a RAID system exactly the same way as their older chips. So, if you have to change mobos, you simply must choose a new one that uses the same chip manufacturer for HDD control as your original board. (I had to do this once. I replaced a mobo with one from a different manufacturer, and using a different chipset, BUT the new one had a more recent chipset by the same maker as the original, nVidia. The replacement board used my two RAID1 array HDD's with no trouble at all - just booted and ran right away.)
The more subtle and confusing options are add-on RAID controller cards that actually contain only a small part of a true Hardware RAID system - the HDD controllers, a small microprocessor and a bit of buffer RAM - but actually are Software RAID systems that use your computer's main components to do most of the computational work of a RAID system. Not surprisingly, these cards are much less expensive than a true "Hardware RAID" system so they look very attractive. The buyer needs to be careful in choosing an add-on card. But, aside from cost, these cards do have one of the advantages of a "true" system - portability. If you move the card and its HDD's to another machine, you have moved virtually ALL of your RAID system, and you are not dealing with a new different RAID controller trying to use old HDD's.