You don't need much computing power with today's hardware level for average back testing. Are you testing on years of tick based data? Is your backtest framework extremely complex and multi threaded? Then you might need specific components. But for the needs you described even a fast quad core CPU is way sufficient. I would rather go for 32gb vs 16gb memory than opting for a 6core vs 4core CPU in case of budget constraints..
OK, here my summary: from what you described you don't need to spend that much on a computer. You clearly are a beginner in this field which is perfectly fine. Get a machine with i5 CPU which is way sufficient for your needs, 16gb or 32gb memory, an ssd drive for the OS, 256-500gb, an a physical hard disk perhaps 2-4tb. Don't ever waste a penny on a fancy graphics card. You don't need that for trading. The computer should definitely lie way below 1000 dollars for such setup, in fact it should costs closer to 700. The Dell machine is way overpriced for what it offers.
And I take a stab at recommending a single machine. You want to spend time on backtesting algorithms not on maintaining 2 or 3 operating systems and machines. With 2 or 3 machines you just doubled or tripped the chance of a defect. A secondary computer comes into play after you found an edge in trading and now want to employ real capital and safeguard against hardware failures. You don't need to worry about a hardware failure when you back test. I believe keeping priorities straight is the most important.
im working back through some of the more helpful earlier posts.. and saw this one
what about this?
http://www.dell.com/en-us/shop/dell...jc0OSwiT3B0cyI6W3siSWQiOiJDSTVTTUwifV19XX0%3D