XPS 8900, GPU upgrade $200

Try to find a good deal on GTX 1070 which would match i7-6700.  This card should be in the 200 range on used market.   For the red team consider RX590.
gtx1080 or 1070Ti is a little bit too strong for i7-6700.

Your processor is too weak for this graphic card on 1080p resolution

Intel Core i7-6700 (Clock speed at 100%) with NVIDIA GeForce GTX 1080 (Clock speed at 100%) x1 will produce 12.12% of CPU bottleneck on 1080p resolution. Everything over 10% is considered as bottleneck.

I’ve seen overclocked ones for a lot more but I case I find a good deal do I need to stay away from those and stick with the regular version 

Duplicate post answered, merged threads.

i7-6700k is slightly faster than i7-6700. XPS8900 bios does not give you full latitude to overclock the -k cpu (Dell consumer bios tends to be user restrictive).  The -k cpu is lot more expensive often because user can over clock to sky limit on non Dell aftermarket motherboard such as ASUS. It depends on you.  If you are not a zealous overclocker, no need to invest in -k cpu for 8900.  It also depends on seller trustworthiness. Do not trust any seller who claims (s)he never overclocked -k cpu on sale.  Better buy -k cpu from friend who is original owner than stranger. You just don’t know how much abuse -k cpu has had.  If seller says -k cpu has always been under liquid cooling and you can trust seller takes good care of components, then maybe consider a deal.