Which CPU cooler should I use?

[tibimakai]

I'm building a PC for BI.
I have lucked out and got a B150 Gaming M3 1151 board for under $30 and an i5-7500 for $100 from CL.
I will get a 80+ power supply, a M.2 SATA SSD for Windows and BI, and a WD Purple HDD.
I'm planning to have around 6-7 cameras. Right now I only have one Dahua 4MP camera, but most likely, the next ones, will be 2MP Starlight cameras.
The question that I have is, how hard will have to work the CPU, to run all these cameras, do I need a big CPU cooler, or I would be fine, with a low profile Noctua L9i cooler.
I will install the mobo with the rest of the hardware, in the cabinet under the 65" 4k TV. I won't be using a case. I will use a fan for exhaust, that will be installed on the back of the cabinet. I already have a similar setup, on the other side of the cabinet.

 

[cutterman]

I just built a BI rig for about 20 cameras using i7-6700k and a basic Asus mATX MB. I picked a Cooler Master (Gemin II M4). It is a nice low profile 120mm fan. With 15 cameras (4MB each) CPU load is 27% and I don't hear the fan.

 

[tibimakai]

I have that fan as well in my HTPC and it works fine with an i5-6500T IC, installed in a cabinet shelf(just the motherboard and the rest of the components).
Since this PC will have a bigger load, I was thinking, that I may need a bigger fan. Since you are OK with that fan, I guess I don't have to worry about it than.
The Noctua should work well, than. I have managed to get, a Seasonic 750W platinum power supply, with hybrid fan control.