First time loading will take some time, because need downloadign 1mb ( that's all html files, images etc... ) but next times might be run more fastly because this internet contents are yet cached by browser. We suggest using firefox, chrome or other browser than IE ( really slowly and buggy ).
But I think you problem is internet bandwidth between your companies locations, are you using some VPN or similar, must investigate in that direction, if locally on your intranet openkm runs correctly then it's a networking problem. One solution in this cases is some external hosting ( but all is conditioned about which security levels do you need, sometimes this solution is not available, then you need to increase bandwich in some way ).
