hi, sorry for my english
mikotik uses for pptp termination.
mikrotik ros 3.20 installed on 2 x intel dual core xeon 3ghz & 2x intel pro1000 server adapter. when active sessions (pptp) > 250, MT have some “lags” and drop sessions.
to example
now mt 3.20 works fine with Intel core2duo (2x3ghz) >400 pptp sessions, but processor loading over 95%
10 firewall rules and shaping all pptp
ether1 = 100-120 rx\tx mbit\ps, 25000 p/s
how can i fix the problem ?
what kind of shaping do you use?
Upgrade to the latest RouterOS version. Some users have reported that fixed similar problems. Not to mention it has dual core improvements and pptp imrpovements! It’s easy 
another test platform (ver. 3.20)
core2quad (4x2,4 Ghz)
2 gb ram
RTL8111 Gigabit Ethernet
now 243 pptp sessions. ether1 = 91rx\88tx Mbit\ps, 24% CPU Load.
I think, you should move from using Simple Queues to Queue Tree shaping. with PCQ, you may shape many clients in one queue
if i move from using Simple Queues to Queue Tree shaping i get more performance?
what about Inter Xeon & MT ?
CPUs will work. Just use latest RouterOS.
CPUs works but performance < core2duo. why?
I see in your first post (not clear but ~understandable post) that the Xeon CPU is 3000Mhz ? So the system has 2x3GHz Xeon CPUs and the Core2Duo@3Ghz outperforms it? Hmmm… How did you test that performance ? What exactly are you comparing?
i’am from russia,
sorry for my bad english )
Server platform 2 x Intel Xeon Dual Core, 2 gb ecc ram (each core = 3 Ghz) This platform can works fine when PPTP = 250-270 Sessions.
And Core2Duo works fine when PPTP ~400 sessions
These results could be different in 3.28… But in both cases these machines should be capable of providing power for more pptp connections …
i tryed 3.28, same results ~250 pptp.
Use them both and balance the load. You can contact me on Skype for assistance about this.
well, I don’t remember what exactly CPU is in our VPN server (2 cores, either core2duo, or xeon), 3Ghz, about 480 pptp sessions, about 27% load
and yes, PCQ performs better then simple queue per pptp session
He is using 128 bit stateless (the default) pptp encryption. And his traffic is 120Mbit +
And hes is a “router on a stick” comes in a VLAN leaves via the same hardware interface 
well, all our routers use 1 ethernet interface =) even those with >600 Mbps bandwidth
Can You share the configuration of this mikrotik which can handle 600 pptp sessions?
unfortunately, no - it’s too complex and not interesting =)