Just wondering if anyone here or know someone who has experience/expertise in hosting dedicated game servers. I only have 5Mbps upstream now (may change to 10Mbps if deem fit) and so far have been very impressed with what I'm able to host and would possibly like to take this further.

So far hosted a few servers without any issue on my gaming rig. But because this is my rig, I can't do it dedicated so I'm looking for an actual server. Planning to do:
2 KillingFloor2, 2 TF2 (mvm and 24 player) and 1 L4D2 server

Would an average spec server be enough?:
Intel Xeon 5*** 3Ghz
16GB ECC 667 RAM

scale? 100ppl?

i think your router also play an important part.

2 KillingFloor2 =12slots
2 TF2 (mvm and 24 player) = 30 slots
2 L4D2 server (1 coop and 1 vs) = 12 slots
TOTAL = 46 slots
Connection wise I think I I'm very safe since it's very stable even at peak. Just that I'm not familiar with server hardware

I just stressed tested the standard UniFi hardware for 24 hours uploading nonstop max without issue. Will keep it cooled just enough.

how many cpu core do you have? srcds doesnt support multicore, so you have to manually assign the affinity(to reduce fluctuation). to stress test srcds server, use net_graph 1 and watch the server fps. put maximum client on server. if the numbers in net_graph is constant(does not drop) youre good. for my 6 32 client server that i hosted, usually a server will accumulate less than 3 megabits per second(for each upsteam and downstream). usually 1mbps+. usually, router wont have problem hosting multiple server. torrents is more heavy than most applications and if your router can survive torrents, your router can definitely survive dedicated hosting.

make sure to include bots slots in your calculation. some game which have 4 or 6 clients is actually have 16 to 32 slots, for both clients and bots.

as for server specs, only choose xeon if you planning on virtualization. i failed to see any tangible benefits xeon have on game server, except of course, virtualization.

choose only intel cpu for your server. some server doesnt support multicore(srcds), so higher clocked cpu provide real benefits. my srcds server each accumulate less than 500mb ram.

you are not using wireless connection for your server right? fibre(unifi) right? are you on high rise building or landed house? you can see fibre cable in your home right? linux or windows? vmware or openstack?