(adsbygoogle = window.adsbygoogle || []).push({}); Processor: 3.6GHz Intel Core i7 4th generation quad-core (i7-4790)
Memory: 8GB DDR3
Hard Drive: 1TB 7200RPM
Optical Drive: DVD/CD
Display/Monitor: No
Additional Specs
Operating System: Windows 10 Home (64-bit)
Memory Card Slot: Multi-in-1 reader supports a variety of memory cards (cards sold separately)
Graphics: NVIDIA GeForce GT 720 with 1GB GDDR3 graphics memory
Audio: 7.1-channel sound output with WAVE MAXXAudio
Wireless Adapter: Wi-Fi N; Bluetooth 4.0
Wired Network Adapter: Gigabit Ethernet LAN
Keyboard: USB
Pointing Device: USB laser mouse
Ports: (6) USB 3.0, (4) USB 2.0, (1) HDMI, (1) DisplayPort, (6) 7.1-channel audio output jacks, (2) Mic inputs, (1) RJ-45 LAN
The Basics
Model #: XPS 8700 (X8700-1572BLK)
Color: Black
Measurements: Approx. 16"H x 7.3"W x 17.5"D
Weight: Approx. 30.4 lbs.
Power: AC power supply
Listing: UL
Country of Origin: China

and you think if I put WIN7 on a hdd would WIN7 boot on this system?

It probably could, but not on Ultra High Settings.

It might play on minimal settings (and even then you still might have issues), but your specs aren't incredible. To be fair your CPU seems pretty nice, but your GPU seems to be poor, and for gaming you want a nice GPU.

Could I use a AMD Graphics Card with Intel CPU?

cuz I only bought the PC cuz it had a better CPU then my other PC & was thinking of taking this PC's CPU and placing it on my older Gaming Rig that can some what run GTAV

Yes you can. AMD video cards are not exclusive to AMD CPUs, and vice versa. They are completely independent from one another.

To further what Rath said make sure your motherboard and CPU sockets match, do NOT force your CPU into place, you will break it.
edit: I moved this to builds since that is essentially what it is
if anything Id suggest taking your other computers power supply and graphics card and putting it in your new computer honestly, the parts would probably be better in the newer build unless you want to provide us with details with that build's specs too so we can give our thoughts on that.

GT 720, have fun playing GTA V.

I don't understand the logic in getting an i7 for gaming.

Change the graphics to a 980ti then you can run ultra

Yes it definitely would be able to play any gta

why an i7 if you get a shitty video card? o.O
Get an 970 its not that expensive and reliable,