Though we have several machines here at Download.com running Windows Vista for testing purposes, I have to admit I haven't made the switch yet at my workspace. Maybe it's because with Windows XP I like the way things are set up, I like the look, and I can rest assured that all my favorite downloads are going to work without fail. I'm not saying Vista won't support my programs and I'm sure I'll make the switch at some point, but for now I'm sticking with XP.

Even though XP is my choice for now, as a major league software nerd, I still try to find ways to improve upon a good thing. Rather than leaving well enough alone, I continually search CNET Downloads to see what programs I can find which will make my OS run even more smoothly. A few downloads I've come across trim down existing apps, clean out system flaws, and keep the whole XP operating system running at optimal speed.

There are many XP enhancers to choose from, but here are a couple I use to give my computer an added boost. Best of all, they're all free!

CCleaner is an extremely popular program for a very good reason: it works great! Whenever I notice my computer is running a little slow, I run this program as my first effort to fix the problem. With excellent cache cleaning capabilities and a registry cleaner, you really can't go wrong with CCleaner. As an added bonus, the included uninstaller works better than the Add/Remove programs control panel in Windows XP. I keep a shortcut to CCleaner on my desktop.

RAMBooster is one of the best programs available to free up RAM in a pinch. If you're getting ready to run a memory intensive program like Adobe PhotoShop, a quick optimize from RAMBooster can give you the space you need to run it more efficiently. You can even have it run on a schedule so you know your computer is using its available RAM the best it can throughout your workday. Of course, if you really want the best experience, you should just get more RAM, but this program is great for those who don't have that option.

Auslogics Disk Defrag is the third and final program in this particular set of free XP speed boosters and is another one of my favorites. It runs much faster than Windows XP's defrag utility and you'll notice a difference in system performance immediately. Windows files and apps become fragmented over time causing Windows to work harder to run smoothly. Auslogics Disk Defrag puts those fragments back together for you to make Windows run at peak efficiency.

If you're not ready to make the leap to Windows Vista, don't worry: Windows XP is still a great system on its own. But if you really want to flip on the turbo boost, download one or all of these free Killer Downloads.