How powerful should the server be?

Question

linux

Hello.
I've finally persuaded my office to buy a good powerful server.
I persuaded him to persuade him, but what he should be like - I'll never know.
The bottom line is this:
The number of users - 50-80 people.
Goals: a domain controller, data storage, a couple of virtual machines, a wifi gateway, a web server (a couple of simple sites for internal use) and a couple more small services.
The case is in a rack (fortunately, the rack is good).
Approximately how much power should the car have in order for everything to work and not lag? I guess so:
Proc - E5-2403
Memory - 2 x 8Gb
Basket - 4 by 3.5
Drives - 2 x 3Tb in RAID 1 for data
2 x 300Gb SAS in RAID 1 for OS and other heresy.
Network - 2 network cards for the gateway.
PSU - 2 hot-swappable PSUs.
All this miracle I get from 150 to 200 k. Wooden.
Then the consultant said that this is very small for my tasks and that I need 100 GB of RAM and 20 cores and a small hadron collider.
Now I'm confused. What should I do? The authorities require concrete commercial proposals from me.
And another incidental question: network card type intel I350 DB has 2 ports. Can this card work on two networks at the same time?
PS
Estimated OS - Debian
Now in the office a server is called a closet in which there are 3 switches and a telephone exchange.
Users arrange anarchy on local machines and are completely out of control.
I have not worked with such servers before - all my server solutions are made on old computers and glued together with blue tape.

Answer 1

Take something for 4+ cores from Intel, 32 gigabytes of RAM, if the uterus allows, then you can use 64 (cheap, but it won’t be superfluous and will speed up the work). According to the disks, it is not clear what amount of data and load you have. If there are no serious loads, then take 4 disks of 2 TB each and them in raid 5 or 10 or 6 (here see for yourself what is more suitable). If the loads are decent (for example, a database), then take a couple of ssds of the required volume to the disks. Such a server from non-brand components (supermicro and the like) will cost about 100-120 k.
P.S. Yes, the card can work in 2 networks.