I'm a long time Photoshop Elements user, currently on V7 but my old XP laptop is getting progressively slower and slower so I'm on the look out for a new PC and thought I'd take the opportunity to upgrade to either Photoshop Elements 12 or Lightroom 5.
Then I started trawling some Adobe forums for info on recommened specs for PCs….holy shit! Adobe's MINIMUM requirements are pretty daunting. Be aware that the applications themselves are huge installs so you'll need plenty of disc space on your HDD. It seems a lot of users on the forums are reporting very slow performance even with powerful modern PCs with Quad Core processors and are recommending both the application itself and the catalog are installed on a solid state drives. (That's gonna be pretty expensive for sufficient SSD capacity if you have a large photo collection)
When I eventually replace my laptop (likely in the next couple of weeks), I'm gonna make sure I get it from somewhere with a reasonable return policy to ensure I get an opportunity to hammer PS/LR to verify acceptable performance (that's assuming I don't find an alternative program in the meantime…)
MAC users: I believe the latest version of LR will only install on 64-bit machines. You may wanna check PS specs as well