According to the test comparison we have compiled in previous post, plus some of our own testing, it implies that FX-4800P is the fastest machine (among all those compiled) around.
The test does show that FX-4800P has a slightly faster CPU than FX-7400G+, though it is marginal. It is a suitable surveyor pal, but not a good one due to memory limitation of only about 4K, IMHO.
Furthermore, it is not in production anymore. So, a good replacement will be either FX-5800P or FX-7400G+. Again, we are still surprise with the speed of FX-5800P in the test. We would like to remind that the test is not 100% conclusive, but it does reveal some information about FX-5800P.