Mixing G Skill Ram

[seabass.devries]

I currently have 2x4GB G Skill DDR3 1600Mhz PC3-12800 CL8 in my Asus P8P67 PRO L1155. I've happened across a single stick of 4GB G Skill DDR3 1600Mhz PC3-12800 CL7. I also have an i5-2500k if that matters. I'm wondering if it won't even be worth seeing if adding the 3rd stick of ram will work because my mobo is dual channel and won't run triple channel, or something like that. Could someone clue me in please? Would this be worth it?

Thanks in advance for any help.

 

[Kasper Jorgensen]

It may or may not work. Mixing up RAM, even same model, can cause compatibility issues.
You will also take a performance hit, at least in some games and applications, as you will no longer run in dual channel.

 

[seabass.devries]

So I currently have my original ram in slots 2 and 4 and when I added the 3rd stick into slot 3 my computer won't boot and the red ram led stays on on the mobo. It does boot with just one original stick and the new stick. I've read elsewhere that this mobo should still boot with 3 sticks. Is there a particular arrangment I have to use with 3 sticks?