Just to contribute to this discussion, I had the high disk IO issue with the 64bit client myself... while it wasn't quite as bad as someone who previously posted, I could not join PvP style matches because it would take so long to load that by the time I loaded in the inactivity timer had expired and I got booted immediately out. Also the character models and parts of the scenery that apparently does not load with the map would slowly fill in over a few minutes after the map loaded. The 32bit would be able to load about 10x faster and I had no issues with load times... it of course had other issues... like running out of memory. After waiting for Arenanet to fix this issue for like a year, I bought a 480GB SSD (for $99 from Microcenter) and replaced my 500GB boot volume with it.... from the SSD it loads about as fast as it did from boot camp in Windows, it is completely playable now. All Arenanet should need to do to replicate this problem is grab a mac with a traditional hard disk and run it in the debugger.... I can't imagine it would be that difficult to diagnose, since the game is basically unplayable from a traditional hard disk. Also a side note from before I replaced the boot disk with a SSD... the disk IO issue would not only affect load times but it would also affect FPS, since when I would move the camera to load a different part of the scene it would start thrashing the disk to load models that were now in view and the game would freeze up while it did that, so it seems like the code that is loading the models is not running in a separate thread (or if it is, it is blocking for some reason). Therefore the FPS would drop to wait for the disk IO .... once all the models visible in the scene were loaded it would play at full FPS. A great example of this is I would stay in the royal terrace facing the asura gate... if I turned my camera the other direction the game would grind to a halt while it thrashed the disk to load the more dense collection of models in that direction.