2 strange issues and I have done everything humanly possible to resolve them.

Details:
Issue 1: When my character is engaged by Yarzon type monsters the game lags and becomes extremely choppy, frame rate, audio, and input all slow down. Problem only occurs when my character or my party members are being attacked, I have been around non-aggressive Yarzon (someones else's leve mob) and no problem. It happens in any zone and does not happen with any other monster type in the game.

Issue 2: Graphics card driver crashes constantly when in Gridania area. It's so bad that I can't even do guildleves at any of the Gridanian camps because more often than not my game will crash before I can finish.

Steps:
- Both problems happen regardless of FFXIV video settings, I have tried everything from lowest graphics settings to highest and both problems still happen.
- I have tried multiple drivers ranging from the drivers shipped with the laptop to the most up to date Nvidia drivers and a few in between.
- Reinstalled FFXIV.
- Reinstalled FFXIV with my roommates install disk.
- This week I reformatted my computer, ran windows update, and installed FFXIV. Same problems, even on a clean install with everything up to date.

Frequency: Always
Platform: PC
PC Manufacturer & Model Number: ASUS G60JX
OS: Windows 7 Home Premium 64-bit
Graphics Card: NVIDIA GeForce GTS 630M
ISP: SHAW Cable
Type of Internet Connection: CATV

I'm sharing the same issue with "Issue 1". I never encounter "Issue 2".

What causes this? Can anyone reply? This has happened exactly as the original poster has stated. What can be done to fix this> Is this a game bug or something? My game runs perfectly, never any issues what so ever, except when a Yarzon engages me, whether it be a single one or an entire mob of them.

Try latest video drivers (came out a week ago). Since it isn't a driver issue, best to use the newest (in theory). If your GPU has the "Optimus" technology, make sure that you have it set to ignore the intel chip. Finally, turn off windows aero and all related features.

Graphics Card: NVIDIA GeForce GTS 630M
This is the issue. Stick an M on any video card, AMD or nVidia, and they seem to have the oddest, most random, and frequently most annoying issues. While this will not help with Gridania probably, it might help with the yarzon (some other people have had similar problems with other mobs at that were fixed by using the steps above).

@ op Issue 2 could likely be related to the system, Gridania is a more taxing zone regardless.
Log your cpu/gpu/ram usage (lots of programs to do this with).
When the game crashes look at what was happening, and/or post a screen shot.
Are the drivers crashing or just the game?
Also could it could be overheating?

Also which tell us your: Cpu (speed too) / HDD / Amount of Ram .. as the model notebook you have as different spec's available.

Not sure on issue 1, I would bug report it with all the info you can possibly give, did it start after a patch? or has it done that since beta? an such.

At what resolution are you playing the game and which CPU is in the notebook?
The GTS 630M in the ASUS G60JX is just above the Minimum System Requirements, and if you are experiencing out of sync/slow audio it points to the system being overtaxed.