Motherboard Choice, and CPU.

If you don't plan to overclock, best to purchase an Intel Core CPU that is locked (i.e., non-"K"), as in your examples i5-7500 or i5-6500. Though the Intel Core CPUs that are unlocked (i.e., "K") as in i5-6600K, has a higher base clock speed that the non-K, the price/performance is lower if you are not going to take advantage of its overclocking capabilities.

If you are sure that you will never OC, then the motherboard that best goes along with those non-K Intel Core CPUs, which are the "H" or "B" motherboards, for example, H110, H170, H270, B150 and B250. Do not get the "Z" motherboards as these are for overclocking the "K" Intel Core CPUs which you won't get.

Generally, you get an i5 if you are just building the rig as a purely gaming PC, and you get an i7 if you are building the rig for both gaming and multitasking/editing work. The i5 has 4 cores but no hyperthreading (runs at 4 threads), the i7 has 4 cores too but with hyperthreading (runs at 8 threads). Most games will not utilize more than these number of cores/threads but there are *some* that *might* benefit from them. On the other hand, multitasking/editing work relies on more threads. So, between an i5 and an i7 -- the choice is yours based on your PC use.

Now the i5's and i7's currently in the market are the older 6th-gen (Skylake) and the latest 7th-gen (Kaby Lake). You can easily identify if the CPU is Skylake based on the 1st digit "6"; a Kaby Lake if the 1st digit is "7". So, the i5-6500 is Skylake and the i5-7500 is Kaby Lake.

This is important as it will also determine which motherboard to use. Like the CPU, motherboards were released alongside the 6th-gen and 7th-gen. As I mentioned above, your choices of motherboards will be H110, H170, H270, B150 and B250. The motherboard is 6th-gen if the 1st digit after the letter prefix is "1"; it is 7th-gen if the 2nd digit after the letter prefix is "2".

All these motherboards have LGA1151 sockets for you to plug in your CPU. Now, BOTH Skylake and Kaby Lake CPUs can be fitted on LGA1151 sockets which all of these motherboards have.

The 7th-gen motherboards (H270 and B250) will support the 7th-gen Kaby Lake and the 6th-gen Skylake CPUs.

The 6th-gen motherboards (H110, H170, and B150) will support 6th-gen Skylake CPUs out-of-the-box. It *will only* support the newer 7th-gen Kaby Lake **if** an updated BIOS was provided by the manufacturer.

So the motherboard you should choose will be somewhat dependent on the CPU that you will pick.

Motherboards also come in different sizes, E-ATX, ATX, mATX, and mini-ITX. The size of your chassis and the total number of devices you wish to plug in the motherboard will be the factors to consider. Consequently, the number of RAM slots also differ (especially for those smaller-sized motherboards).

Motherboards also come with several optional features depending on the model. Some have built-in wireless connectivity (wifi and bluetooth). Some have dual LAN RJ45 sockets. Some have dual BIOS (main and backup). Some support multi-GPU configurations (Nvidia SLI and/or AMD CrossFire). Some support USB3.1 front panel ports; some do not. Some have LED lighting features; some don't.

You need to determine your requirements first in order to carefully select the best motherboard that suits your needs.