Hi guys it's my first time posting here so please correct me if I'm posting in a wrong format. Pardon me for the long post.

I am a drk in reboot.

So there are several issues I have noticed.
1. When I join a ursus fight, once I got in the map, I lag(can move but can't use skills or even flash jump and other people not moving as well). Then a dc occurs afterwards or I just quit.

2. When I train in river maps/clock tower, I lag( mobs experience delayed death and I'll have a short period of not been able to cast skills)/sometimes dc

3. When i train alone with kishin, same situation as (2) when I use aoe skills/kill very fast. Sometimes the GM message will pop up and kick me out because the delayed death caused large amount of mobs to die together at the same time.

4. When I'm in a same map with a high speed class or many atk lines (NL/DB/DS), I tend to lag( can move while other boss/ players are seen standing still). For example, going to Hmag with a DB will cause the situation to occur and the meteor rain will occur even though I didn't dc/or did dc. Another real example is when I go lotus with DS, I can attack but everybody else seems to be not moving until the phase is over then it starts over again at a new phase.

5. This might not be related with the above situations but I'll add it just in case. Selling items through NPC has a delay. Takes a few seconds for the item to appear on the buyback after I sold the item. Equip/unequip nodes in v matrix takes 3seconds. Inferno fox ending sooner or later than time limit.

Methods tried
1. Delete and reinstall maplestory in different locations/harddisk (ssd or hdd) using both nexon launcher/steam. Doesn't work.

2. Change compatibility of maplestory.exe to windows xp service pack 3( I was using windows 8.1 enterprise) and it worked. What happened was I was able to ursus for the first time, boss with an NL, train with a kishin alone or with a friend. I faced another problem where when I play for a longer time and hit many lines, my memory increases from 800mb to 2.1gb gradually. And fps drops in game, but that could be solved by turning off the SFX sound in game or restarting the client so it's alright.

2.1 After a few days, and if I remember correctly that it was after the recent weekly Thursday maintenance, the old lag came back and this time I tried changing the compatibility to different options but didn't work anymore.

3.Downloaded all Visual c++ runtime. Updated graphics driver. Didn't work.

4. Change maplestory priority to high and tried setting affinity to only one core from task manager, doesn't work.

5. So I bought a windows 10 key and decided to wipe both my harddisk clean and change to W10 instead( was planning to change anyway) and tried again. Problem still persisted.

So I actually have no idea where the problem is because it did manage to work smoothly for a few days, which I think it means there shouldn't be a problem with the hardware?Or could it be the RAM, since it was bought individually instead of kits even though both of them are of the same brand/type. I have a gigabyte z170 hd3p mobo, i7 6700, gtx 960, 4x2 ddr4 ram, 120gb ssd and 500gb hdd in case it matters.

In a nutshell, I think the main problem could be the game couldn't load fast enough so it tends to stop the motion of everything while loading until it's done then all the effects occur at the same time instead of letting the game continue while loading data. Though I still ran out of ideas to fix it.

I'm hoping to get help or suggestions from anyone or possible solutions from people who have experienced the same problem. Thank you very much.