this is on a base 2.4ghz mini with no upgrades: i normally don't have this many apps open simultaneously, but i wanted to show what would happen to 1080p video when all the ram is used. notice the swap file is nearly 2GB. normally it's less than 128MB with half-dozen apps open. even with this many apps open, 1080p h.264 videos (quicktime mov container, bluray rips in mkv, etc.) play just fine (tested with quicktime x, vlc, mplayerx). no stuttering, no dropped frames. the cpu still has a lot of breathing room. even 1080p flash videos on youtube play fine with the new h.264 gpu decoding in flash 10.1. if you have video playback problems, simply throwing more ram at the problem is not necessarily the solution. you may hear many people recommend going to 8GB of RAM on their mac mini without actually qualifying the reasons for doing so. if you have a legitimate need for 8GB of RAM because you use apps that require a lot of RAM for adequate performance, such as hd video editing, 3d games, or virtualization software, then by all means upgrade to 8GB. but if you're using the mini as an htpc or for general computing purposes (web, email, itunes, ilife, iwork, etc), 4GB should be more than sufficient. and really even 2GB is perfectly adequate for basic htpc needs as shown by my example. people tend to freak out when they see their free memory get low. but memory is SUPPOSED to be used, and snow leopard is pretty good at handling memory resources. when someone boasts about having 75% of their 8GB of RAM free and all they're doing is watching videos with their mini, that just tells me they wasted their money on 2x4GB modules. so don't upgrade to 8GB of RAM just because someone said having a lot of free memory makes your system run better/faster. depending on your needs, 2GB-4GB may be all that you need and 8GB may be overkill.