What cpu is this? and what should I buy?

[Achmedsback]

I volunteer in a club at school where we fix old computers for students who are in need of a computer and cannot afford one, we get donations and go from there. We have some older i7, i5 and AMD phenom boards and CPU's that we keep for the volunteers, I just found out that I am allowed to Frankenstein together a pc and I'm not sure if some of the parts will fit and I'm looking for some recommendations. This will be my first custom build.

First off I found an HP pavilion with a socket 115x. the cpu is an i7 and that's all I know (note there is a windows 7 sticker on it, this may help to date it.) My first question since I plan on upgrading the motherboard later on to a z97 variant, will this CPU work or should I get a 4790? For a follow up question if I get a new cpu should I get the 4790 or 4790k? I don't want to overclock a new processor and plan on using this computer for CAD, simulation, and Starcraft Gaming. I would like to stick with Intel 1150 sockets.

My possible build consists of
- full ATX Coolermaster Case
- HP pavilion 115x socket mobo with multiple pci and pcie slots

- 16 gb DDR3 (not sure about speed, any recommendations)
- 550W power supply *I think it's a bronze rating
- not sure about a GPU I need to purchase one I plan on a dual or triple display when I upgrade
- I need a heat-sink, we have a ton laying around and I'm not sure if they will fit (should I get an aftermarket cooler or scavenge for one)
- 500gb HDD


That's pretty much all I have for now aside from several misc parts like fans and optical drives, I plan on upgrading in the first quarter of 2017, I know that AMD is supposed to drop their new line of GPU's and CPU's so prices for everything else are probably going to drop. I am looking at the GTX 1060 and 1050 GPU's and recommendations
Thanks if there is anything else you see that I may need or any specific brand or part please respond. My budget overall is $600 without a CPU, and currently $300. If I can put a decent GPU in now I will.

 

[Vic 40]

Look at the cpu itself for info on which one it is if the system isn't working right now. If it is in working order could you do this,

download hwinfo32,
install and open it=click run,
close the top window which is the system summary,
at the left top click "save report",
at the bottom of the next window check "short text report",
after that you'll see what's in the pc

 

[Achmedsback]

So I looked at it again today and found it is an i7-870. The socket is lga 1156. I haven't been able to work on it yet so im not sure if the MB, CPU, or anything works. I talked to everyone and it supposedly works fine I just need to piece it back together. I found a heat sink that will work fine with it overclocked a little. Now my first follow up is, Will this cpu work for moderate games and higher cad/ simulation programs?

But I don't know where to start with a GPU, I was told to get either gtx 1060 or 1050, or wait for AMD to drop their new line in the first quarter of 2017 for Nvidia to lower their prices.
Second follow up question if, If I go with the 1060 should I get the 3GB or 6GB version? Or do you have any recommendations for a different GPU, looking in the $300 max range.
The mother board is a standard Proprietary HP motherboard (HP Pavilion Elite HPE-450f), Will it fit (as in will the holes line up) in the Full tower coolermaster case? I have plenty of standoffs and im capable of drilling new holes if I must.

Thanks Justin