Sorry to kinda necro post but anyway,
I have a Dell T3500 with:
Xeon x5650 6 Core 12threads 2.66ghz
22gb ram(I can go to 48gb, maybe even higher since the RAM Controller is on the CPU, the RAM limit is 228gigs)
EVGA 500W 80B PSU
The PSU is a standard ATX psu, I threw my EVGA in no problem. I just needed to remove the motherboard to do so since Dell wires the CPU cable beneath the motherboard. This isn't a hard or overwhelming task, just remove the cooling fans, then the motherboard screws(and whatever else holds it down). Install the PSU then the Motherboard.
Above is me using the EVGA PSU, beware the CPU pin is a 8 pin so you'll need a better PSU than your average case one. Corsair and EVGA are what I trust, but if it has a 8 pin and you trust it, go for it.
The X5650 is probably the best budget CPU for the money. You'll get way more performance with it. Every game I play loves it. Mine was 30$ and benchmarks very similar to current i7 4000-6000 series processors(certain, but I forget which) and like I mentioned, removes the 24gb barrier allowing you 8gb sticks or higher possibly. Also make sure you have the copper heatsink revision for your CPU. Temperatures will be way higher with the old version(or at least that is reported). The heatsink is model U016f.
RAM was an absolute nightmare for me(ended up buying and returning ram twice, and I'm still stuck at 22gb). Buffered RAM is not liked by the T3500. Higher rank memory is also disliked(ex. 2Rx8), pretty sure 2Rx4 is the best way to go. But my tests aren't finished yet.
The GTX 1050 doesn't use external power(it does depend on the manufacture), so you could just run it off the native Dell PSU I believe. Even at most the 1050 would just need a 6 pin, which a Dell T3500 PSU has(if not molex to 6 pin works)
Here's a finished picture above:)
Hope this helps!