Relatively new system rebooting alot, shouldn't be a BSOD

Well the kit you have chosen looks fine,
First of all verify what voltage the memory stick you bought are at the correct voltage setting and timing settings in the bios.
If for any reason the memory has an xmp mode make sure your memory is set to that value in the bios.
Why do I say this because some memory from say 1333Mhz to the 1600 Mhz range requires xmp mode and the voltage can go from 1.5 to 1.65. though it seems small enough of a voltage change it can mean the difference with some memory becoming unstable under any sort of load, so should be checked along with the correct timing values of the memory. Under volted memory can be the cause of random restarts of a system with no error messages reported.
So I suggest even as a trial if you can to up the memory voltage about 0.25mv if you can in your bios see if it becomes stable with no restrts of your system.


Your second thing to look at if new or not is your xfx PSU. that it does not suffer from power spikes or what we call ripple effect where the voltage can fluctuate rapidly from a minus voltage level to a plus voltage level. To a point it should always stick to a fixed voltage level on all of the outputting power rails. And becomes more evident when heavy load is applied to a PSU or under load strain.

This can throw sensitive parts of the pc that require a steady and smooth power supply. You may need a slightly higher rating of PSU, have a look at how many amps the Nvidia card you have draws from your PSU and verify if the PSU has enough amps to provide the card with its amp requirements, with spare amps enough to drive the rest of the components in your system like HD`s and dvd drives or SSD drives - (use less Amps watts.). Amps are just as important as the amount of wattage a PSU can output.

If you have little or low amp rating on the 12v power rails it can cause all manner or restarts of a system, as the amp and wattage requirements fluctuate for example when you fire up a graphics card for game play.
If the restarts are more evident when playing a game it needs looking at as the possible cause at 550w peak output you may be right on the edge of what is required.