Mixing Ripjaws X and other memory

[alba]

My ripjaws memory are too high for my CPU cooler. I got a pair of crucial 4Gb to install in slot 1&3 instead.

Would the ripjaws memory work with my crucial pair if I put in both pairs? The motherboard manual recommend installing same memory type in all slots.

I am not interested in overclocking just stability. Is there a recommended way to test if the system is stable?

Memory:
G.Skill 8GB (2x4096MB) CL11 2133Mhz Ripjaws Gaming
11-11-11-30 1,5V

Crucial Ballistix Sport 8GB 1600Mhz (2x4096MB)
9-9-9-24 1,5V


Motherboard:
MSI Z77 GD65
CPU:
Intel i5-3450 3,1 GHz
Cooler
Arctic Freezer 7 rev2

[Tradesman]

You can try them together, manually set the timings to 9-9-9-24, 2T, and 1.5 DRAM Voltage with freq of 1600....might work, if you get BSODs etc, try DRAM voltage up to 1.5 and raise CPUVTT to about 1.16