Leaderboard

Much depends on where you need the system for, so I'll just go for the generic details. They're both refurbished and probably returned for a reason. Both have Nehalem CPUs, which offer good performance but at a cost. The W3520 has a TDP of 130 watt, and if the cooling system was skimped on, it will overheat. The other system has 2x60W CPUs, which should be easier to cool. The dual socket system has 8 slower cores, so it will only provide a notable speed increase over the single socket system if the software you run is heavily multithreaded. Oddly enough, both systems are triple channel yet run 4GB, so that's dual channel at best. The single socket system has a mere 500GB harddisk, and the dual socket one is anemic at 250GB, which would probably require you to replace it. The FX1800 is based on the peculiar 8800GS, and I have no idea if it's useful in any way.