His problem may be simply dialup modem 56K bandwidth;
I can play acceptably at 33.6 Kbps here; for 2 PCs on at a time one hangs a lot while the first runs well. I'd have to suggest minimum 40K bit per second for each PC, so 2 PCs need 80 Kbits per second (64 KB/sec) real speed. I find EQ 2 needs too much concentration to run more than 2 PCs at once, even if I had many more able to run EQ.
For Korea, there's an excellent national broadband; so if he has broadband (cable modem), the next issue is if theres so many people using the service AT THAT MOMENT that lag is an issue (more people means less real bandwidth, less speed at that moment).
There are some web sites that measure throughput at that moment. Try these
(only works in USA only, grrrr)
http://tech.msn.com/downloads/speedtest.armx
(has a UK target, some USA targets)
http://www.toast.net/performance/
(looks like it tests a single site in USA)
http://bandwidthplace.com/speedtest/
and see how you're doing when it seems slow. Close EQ 2, run it and see. Now run it early in the morning and compare the difference...
And finally, heres a useful link:
http://www.internettrafficreport.com/main.htm
double click on the continent to get router useage and ping delay times at different points around the world. This helps plan where to download when you have a choice of international sites, by knowing the last 6 minutes or so traffic in each country, past certain high speed routers.
These links aren't something running in my garage; I look them up using
www.dogpile.com <-- which then queries several search engines in parallel and organizes the results. Not fond of google hijacking the search to reward advertisers. Your opinion may vary.