"Full Party" and "Light Party" effects cause lag

[CSLionheart]

Occasionally (I'd say about 30% of the time) when I join a party, or when I'm in a party that becomes a full party, when the "Full Party" text pops up on the screen, it causes extreme amounts of lag to my client, to the point where the game becomes unplayable. Not only that, I've found that it actually slows down the rest of my running applications as well (for example if I alt-tab out into Chrome, as I play in windowed mode). The only fix that I've found so far is to fully exit the game and restart, which is very inconvenient, especially in Ifrit groups, etc. Another member of my linkshell also experiences the exact same issue, very frequently at the same time as me if we're in the same party.

I've also noticed recently that the same issue occurs during guildleves, at the end of the leve when the "white flash" appears signifying that you were victorious. Once again, it causes lag to the point where I must restart my game. If it helps, my PC hardware specs are as follows:

-Windows 7 64-bit
-Intel Core i7-960 Bloomfield @3.2 GHz
-nvidia GTX-480
-6 GB RAM
-speedtest:

-pingtest:


Let me know if you require any other information.