I have recently upgraded my ram. I went from 2x4 to 2x8 Gb and now i get random blue screens. The ramsticks both work solo but when I run them both they crash. Memtest86 didn't show any errors. My PC specs are: i5-4670, MSI H87-G43 motherboard and Crucial ballistix sport 2x8 1600Mhz ddr3 udimm 1.5v