KAELERIA! Nice attitude jerk! How old are you 12? I have a better computer than you do NYAH NYAH. This system should be adequate. It is 3.5 yeras old and had absolutely no issues with LR 3 or CS 5. If the system needed a specific minimum hardware Adobe should have said so. Your comment was SOOO MUCH help.
No need to compound one bad attitude with another and then add name calling and juvenile behavior as well. These forums are better than that.
You should have listened to the message instead of zeroing in on the attitude. It's a fact, your computer is very under powered in all respects (memory, cores, operating system, (probably drives as well)) to run LR4 with any degree of comfort. And it's a fact that LR4 requires heavy resources to run well. We get thread after thread after thread with people going over the same issues/thoughts. Hint: There is a search feature on the forums. Or, just read down a page or two and you'll pick out 3-4 other threads talking about LR's performance.
What performance was acceptable to you with LR3 probably won't be achievable with LR4 on your system, but it shouldn't be a huge difference.. more like incremental. I assume you've optimized your catalog, defragged your drives, made sure the drives aren't more than 60-70% full for best performance, went over MSCONFIG and minimized which programs start by default every time you boot and consume resources, configured the caches for best performance on your system, reduced the size of your previews, and done the proper maintenance on your system to ensure it's running at full speed and isn't being throttled due to heat issues or the like?
People come here looking for the magic pill to cure cancer and it's just not available. LR requires powerful hardware.. personally I love LR and I have no performance issues save for a 1/2 second delay it takes to apply changes to my 2nd screen.. and that's only because my video card was recently replaced with a less powerful version. Before that there was no delay. I'll live with it until my next computer upgrade.