Every Developer Deserves More Memory
manyniches.com
manyniches.com
That is why, more often than not, I've deliberately worked with hardware that was a generation or two behind the latest and greatest. Yes, it is a PITA. Yes, I'd enjoy the bright and shiny. But it keeps me honest about what is going to work in the wild.
You can't combine it into a single computer, because even if it is only 80% of the latest and greatest, it is still way faster than grandmom, thus not representative of your customer base.
Instead of having a second crippled computer for testing, I would rather use tools like Charles (http://www.charlesproxy.com/) to cripple my computer in a tweakable and consistent way.
This way I can develop, optimize for certain controlled conditions on the same machine, and verify my optimizations with real people.
Only one very, very big drawback: you'll want that much RAM in every system you use afterwards. I guarantee it: I just put back the screws on my laptop 10 minutes ago ;-)
Here's a link about it - http://forums.macrumors.com/showthread.php?t=573906
Moore's law yadda yadda, but while it's great that we don't have to include inline assembly anymore, some of the waste we're seeing currently is just abysmal.