I was a bit skeptical of storage-tiering program TierOne ($10, buy-only), and you'll see why later. But first, what's this storage tiering that I speak of? It's simply moving frequently accessed operating system or data files from a slower drive to a faster one, and accessing them from there. The strategy is employed extensively in large data centers to increase performance without breaking the bank by using small amounts of faster, more expensive storage with larger amounts of cheaper, slower storage. TierOne aims to do the same thing at the single PC level.
TierOne works by leveraging a fast solid state drive on a system that uses only plain ATA or SATA hard drives, though it could also work with faster and slower hard drives. I tested TierOne on a system with a decent but aging Seagate ST1600023AS, 7200 rpm hard drive, and Windows 7 and added a Kingston V Series SNV425S264 SSD to the mix for use by TierOne. The V Series is certainly not the fastest SSD out there, but fast enough compared to Seagate.
When I turned off Windows's file hiding to see what TierOne was doing, the first thing I noticed was that the Windows page file and temp folders had been moved to the SSD as I specified when I ran the program. That's a good thing, but it's also something most users can easily accomplish by merely changing drive letters using System Properties\Advanced\Performance Settings\Advanced\Virtual Memory and System Properties\Advanced\Environmental variables.
I was expecting to find something else; however, there is no service or background process to find. Without an active component redirecting I/O, TierOne is merely a $10 utility that changes a few Windows settings. The vendor, TierAge, was quite forthright in confirming to me that this was all the program did and said there's a real-time TierTwo in the works that does more.
Since I spend a rather large amount of time setting up a system to test TierOne, I went ahead and benchmarked with and without redirect. Redirecting the temporary files to the SSD resulted in about a 5% improvement in overall system performance. As the benchmark covers CPU, GPU, memory, and hard drive performance, that's more than it sounds. Subjectively, the speed was most noticeable when installing a program, an action that makes extensive use of the temporary folder.
So, long story short: Yes, you can improve overall performance with an SSD. Yes, you can increase performance by redirecting files to it if you don't want to reinstall Windows. No, TierAge is not necessary unless if you really don't like editing Windows settings. Also, you might get better results either copying the entire Windows installation over to the SSD using an imaging program, or simply reinstalling Windows onto it.