In the past, when I've done development work for work (which, admittedly, didn't go beyond utilities we needed for given tasks, so was never anything massive), I've always used two machines. I used a relatively fast one for development, as I usually code in C++ and most c++ compilers (especially Visual Studio, although I prefer not to use that) do really benefit from a fast machine with a lot of memory (although it seems to be the memory that generally provides the most benefit). For a test machine, I used the oldest, slowest machine I can find.
Why? The users that actually used the little apps and utilities I wrote were not likely to have had the latest and greatest CPUs and Graphics Cards. They would not necessarily have masses of memory in their machines. I needed to see what the users were seeing.
Reminds me of a story I heard about George Lucas. Apparently, when he had finished Return of the Jedi, he went to a local cinema to see it. When asked why, he replied that he had only seen it in Hollywood screening rooms, which always have the best projection and sound systems, and screens. He wanted to see what the man on the street would see when he watched it. Apparently, he was appaled, and that did lead to the formation of THX.