Western Digital regular red, plus and pro hard drives, why 5400 over 7400? Which would you recommend for Synology?

[cfojo]

Western Digital has regular red, red plus, and red pro hard drives. As a regular home consumer, I bought some WD RED PRO's at a really great price during Prime day and I notice it's a 7200. I couldn't find it on Synology's compatibility list for the ds1621+ or ds1821+. Three questions as I am totally new to this:
1. Could they still work and be used with those Synology NASs?
2. Is 5400 better than 7200 in HDDs?
3. If you were me, buying a NAS for the first time, what would you recommend?

[ed]

Yes, Synology is not updating their compatibility lists often. But I can assure that WD Red pro will work. In fact these drives should be o their recommendation list. With a 6 or more bays in a NAS (8 bays + for sure) people do consider high performing drives. Often they add 10GbE connection which demands for a high performance drives in order to enjoy full 10GbE speeds.If a NAS is located somewhere in a living room, choosing slower spinning drives (5400-5900RPM) make sense. In comparison with 7200RPM always spinning disks, regular NAS drives will hibernate when not in use. This saves energy and generates less noise.Speed wise, both drives will perform at similar speeds when active. I hope this helps.