CleanMem I've got to talk about this little program that another category editor told me about. I've been running it now for several months and I've got to say that I almost forgot about it. You never notice it other than you eventually notice that your system is running smoother and faster. After installation, you don't even realize that it is working. The program will install and set it to run every 30 min via the windows task scheduler. You can change this to any amount of time you like by simply going to the task scheduler in windows and changing any of the options you like.
Install it and your done! The program doesn't run in the back ground, once it does its job it closes and doesn't run again until the task scheduler runs it. The program is very simple to operate as it will run and clean the memory out of all processes it can, without any user input.

This doesn't work like other memory cleaners that do nothing but force windows to free up memory by using up all the avail. memory. This old trick then causes your system to lag big time!

FreeRAM XP is a memory manager that not only works but also doesn't seem to cause problems; a rare combination. It ticks away in the background, consumes few resources, and does genuinely free up a bit of memory when you ask it to. It can also be configured to automatically free up memory.

Does freeing up memory improve performance? On both my test system and personal laptop it certainly did release some more memory, but it didn't make much difference to performance. Still, all my systems are XP and have 1GB plus. Maybe on older PCs with less memory, or when using applications like PhotoShop that eat up a lot of memory it may make a difference, I can't say. What I can say is that FreeRAM XP caused no problems other than a 10-30 second freeze of my PC when FreeRAM is in the actual process of releasing memory.

MZ Ram Booster (http://mztweak.bravehost.com/) Please be advised that MZ Ram Booster requires .Net Framework 2.0 or higher.

RAMBooster 2 (http://www.sci.fi/~borg/rambooster/). There are actually 2 videos on CNET TV (http://www.cnettv.com/) featuring RAMBooster 2 that speak highly of the program. If you are interested, just follow the link and do a search for RAMBooster.

CachemanXP (http://www.outertech.com/index.php?_charisma_page=downloads) While not solely a Memory Optimizer, I also need to mention it. CachemanXP is somewhat unique. CachemanXP is a Windows tuneup utility designed to improve the speed and stability of your computer by optimizing several caches, recovering RAM, and fine tuning a number of system settings. Oneclick-Optimization makes it suitable for novice and intermediate users yet it is also powerful and versatile enough for computer experts. Backups of settings ensure that all user modifications can be reversed with a single click. CachemanXP requires Windows 2000/2003 or XP/XP64 to run, uses minimal resources and virtually no CPU time. It does offer a Memory Optimizer as a part of its package.