Replasing our HP 380P G8 to a G10? What CPU brand?

Today a company have a DL380P gen8 with E5-2620 v2 CPU, 32GB RAM, 2x120GBSSD in R1 as system and 5x300GB 6G SAS as storage, and they want an upgrade, mainly because of need for more space on discs.
The DL385 Gen10 seems quite fine as an replacement, but I see some of them is delivered with AMD EPYC 7251 and other AMD cpu's.
Is the AMD cpu 100% compatible with ClearOS? And is there anyone with some advice for what series of discs to look for?
Usage is very intensive to email (Zarafa today), they use attachments up to 50MB in mails, and they have alot of these mails, there is the hickup today. They demand no waiting time to get their emails up and running. Using Thunderbird on W7/W8/W10 clients today. No virtualizing today, maybe a old WXP as "fileserver" for some waterjet machines who run good old DOS as OS.