I purchased the XPX 8700 with the max available 16G, but it can be expanded to 32G, and I think I need to do that.

What CAS latency timings does it require? The most common seems to be 9-9-9-24, but there is also 8-8-8-24 and 7-8-8-24

Also what voltage should I buy? - available are 1.5 and 1.35 V