I used this some time ago. But I realized that you don't really see any performance improvements by using RAM drives.
One thing ppl add to their RAM drives is the temporary internet files folder. For me, it only made it worse, since I lost all cached files on rebooting the system.
Anyways, I continued to use it until I realized that the problems I was having with large downloads was due to the RAM drive itself. I download Linux ISO's quite often, and they're large files (around 700 MB each). I found that since ongoing downloads are stored in your temporary internet files folder, my 700MB ISO's were getting truncated to 32 MB (the size of my RAM drive back then). Obviously there was no way I could get a RAM drive large enough to accomodate such large downloads, so I gave up on that altogether.
Since Leedogg asked for a free RAM drive app, I posted a link to it. I didn't mention my experiences, since different people have different opinions about RAM drives.
There is absolutely nothing wrong with the software I posted. It works as it should, it's free, and installation is easy. So give it a try. If you like it, keep it. If you experience troubles like I did (not with the software, but with RAM drives in general), or see no benefit using it, it doesn't take long to uninstall the app.