Hi,
Test Your memory's
Run Memstest86+ Download and install Memtest86+ it's a free s/w
http://www.memtest.org/
Create a bootable CD/DVD or USB-stick, it is a very small program, it will easily fit on a CD.
Then boot the computer from this, Memtest86+ will automatically start, and don't worry - it will not in any way compromise nor touch anything on the hard drives.
You must run Memtes86+ until at least pass 8,9,10 and 11 (it uses different test pattern then) and for 8GB of memory with an Intel 2600K it will take the whole night, approx 4-5 hours, if 16GB memory - twice as long.
If an error occur, You can just shut it down. Then You know that it is a serious problem with your memory's.
Take out all memory stick but one and run the test again - it will be much faster.
If no problem, replace the memory stick and run memtest86+ again so that you now which memory stick is faulty.
The second:
When it comes to memory's there are a few things to keep in mind:
1. Always install memory sticks from one memory kit. They are matched together.
2. Always make sure that the chosen memory's is indeed supported by the motherboard and its processor.
Different types of memory's, different frequencies, timings etc. the memory stick with the lowest speed will always set the speed for the rest of them.
3. Very important that the voltage of the memory are supported by the processor; meaning that a memory stick with to much voltage let say 1.65V when the processor spec. clearly says 1.35V - will damage and shorten the processors life span.
4. Make sure that the height of the memory modules can fit under the CPU-cooler (if it is not original).
Use a memory configurator such as
Corsair
http://www.corsair.com/en-us/memory-finder
Kingston
http://www.kingston.com/us/memory/search/options
G-Skill
http://www.gskill.com/en/configurator
Etc.
But even then, som memory manufacturers recommend memory's with a little bit to high voltage, so make sure that the CPU manufacturer specs for that particular model of CPU is followed regarding the memory voltage.
Otherwise it will shortened the CPUs lifespan. Over Clocking is always a risk.
For ex. a processor of 2:a generation Intel Core i3, i5, or i7 of Sandy Bridge alt 3: generation "Ivy Bridge" etc. these should have 1,5V +/- 5%- memory's.
For DDR3 memory: 1.5 volts, plus or minus 5%
For DDR3L memory: 1.35 volts, plus or minus 5%
For DDR4 memory: 1.2 volts, plus or minus 5%
Best regards from Sweden