different ram sticks

Hey there. Some days ago i bought a new 8 GB corsair vengance RAM stick to upgrade my current RAM. But it didn't really go as planned. As it turns out my already two 4 GB sticks refuses to work with the new 8 GB stick. When i tested it the computer refused to even start until i took it out. I...

i need suggestions for most compatible rams with CORSAIR VENGEANCE LED 3000mhz CL15R...i already have 2x8gb ram sticks...i need 2 more so i can make upto 32gb....rams doesnt have to be of the same brand....also its not necessary they have to be RGB

Hey, I've currently got a G. skill 1x8Gb Ripjaws V 2400mhz CL15 overclocked at 3000Mhz CL16 at 1.25V. I'm currently getting a good deal on a 2 Years Old USED Corsair Vengeance LPX 1x8GB 2400Mhz Probably CL16 (where as G.skill is CL15 at default). Should I get it or is it worth to spend more to...