Though we have several machines here at running Windows Vista for testing purposes, I have to admit that I haven't yet made the switch 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 to make my OS run even more smoothly. A few downloads I've come across trim down existing applications, 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!

Once you\'ve cleaned the cache, check out the issues section to scrub the registry. (Credit: CNET Networks)

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.

You\'ll be surprised with the results you get from this simple application. (Credit: CNET Networks)

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 such as Adobe PhotoShop, a quick optimize from RAMBooster can give you the space you need to run the program 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
Watch as Disk Defrag puts your files back together. (Credit: CNET Networks)

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 applications 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.

Jason Parker has been at CNET for more than 13 years. He is the Senior Editor in charge iOS software and has become an expert reviewer of the software that runs on each new Apple device. He now spends most of his time covering Apple iOS releases and third-party apps.