I use Hotspot on RouterMaxx 8. It's x86 system. Now I have more than 500 concurrent users.
Now I have a problem with opening login page or splash page. My clients can
not use browser to open login page be course they see "Server do not found". But when I try
to resolve domain name through command line on client OS or via Linux system all work great. I used RouterOS 5.7. Now I upgraded my sistem to 5.8 . There was from 50 to 75 mbps of bandwight, average 8000 packets per second and 40% cpu load.

My clients can't open login page. I found on Mikrotik forum same problem.
http://forum.mikrotik.com/viewtopic.php?f=2&t=56150
Now I found next observation:
1 When client authorized there is no problem with DNS and internet.
2 When client do not authorized there is problem with login page.
3 Problem occur not each time, but if client see it he can try to open login page or splash page 2 or 10 time before it will open.
4 In web browser I entered URL something.com. After 5 times of trying I watched login page. I did not write login and password. I wrote new URL secondthing.com. I need to try again several times before I see login page.
By the way I noticed. When this happen external hotspot login page opens immediately. Internal Mikrotik login splash page opens in 30 - 40 seconds.
If I try to open http://172.16.0.4/splash or http://10.0.0.1/login I do not see a problem. All work great using ip address in URL.

How can I solve problem?