Hello and welcome to the forums.
I concur, let the array do it! The windows server will only dedupe data on that one windows server, no global dedupe bewteen windows servers. The Primera will dedupe all data stored on it. Also the Primera has specialized ASICs to assist with dedupe hashing.
One article that you may want to look at is the StoreMore guarantee offered with Primera. The guarantee does not apply when the data is already deduped/compressed/encrypted by the host.
https://h20195.www2.hpe.com/v2/Getdocum ... skiphtml=1