It's perfectly fine to use that memory from a P55 build in newer builds. Also Patriot's normally take about 1.7V. Intel may say to stick to 1.65, but also remember most of the memory speeds are something like 1333 without having to overclock (I think the x58's memory speed was 1333 by default?) So go ahead, use what you have and don't worry about it. I've been using Patriot memory exclusively for my last 6 builds and only one issue (my motherboard, not ram related) even having to overvolt a little. Also, if you keep the speeds at 1333 on that viper 2 (if it's the 1600 mhz, CAS 7 version) then 1.65 will be fine. Some of their "gamer" memory uses cas 7-7-7-20 and you need to adjust speeds in BIOS and all that. Most folks who just upgrade don't want to deal with it. So if your not comfortable tweaking memory timings, just get some other ram. If you don't mind doing a google search, and messing with things a bit, keep your current ram.