So I want to upgrade the RAM on my older Asus P8Z77-V PRO Motherboard. I have the Asus QVL list, and it documents RAM anywhere from DDR3 2600 OC to DDR3 1800 OC. Then it lists the DDR 1600 and 1333 non OC. I currently have 2x4GB 1600 CMZ8GX3M2A1600C9 in dual-channel mode which is on that list. My question is, should I stick to non-OC speeds (1600) if I'm doing a RAM upgrade or is going as high as I can worth fiddling with the timings/voltages and/or is higher DDR even noticeable if the rig is 20% low end gaming and 80% work (VMs, application development, etc). Also does it really matter if it's on the QVL list because lots of this RAM doesn't exist anymore.