As of 2.1 I notice on both my machines massive / FPS issues in 25man raids specifically. There's many posts on Blizards own tech support forums about this as well -- including several blue stickies with GM's making comments to the like "we cant reproduce this inhouse yet".
I am going to turn seveal key mods I use tonight off for Magtheridon but untill I try this has anyone else experienced this and tried to turn mods/etc off to see what is the cause.
I use about 20+ ACE2 mods atm on a machine with a 7900gtx - 2gb ram and Core2Duo on XP pre 2.1 everything was fine.
I am going to turn off PitBull/Cartographer/ORA2 one by one tonight time permitting in Magtheridon's lair and will post any info I find out...
Not gonna register on EJ's boards just to post this, but castsequence and conditional macros now do constant processing to figure out what spell is displayed on buttons.
Moreso, the ChatFrame.lua errors that are all over the place (if you /console scriptErrors 1) when you're using castsequence macros happen OnUpdate -- and processing the error path is likely more costly than doing the checks it's supposed to do.
The same thing happened to me when the patch hit. I don't know if it was the addon itself or maybe a conflict, but switching from Infinibar to Bartender3 made the crazy lag I experienced in 25 man raids (it wasn't as noticeable in Karazhan) disappear.
i belive this because pitbull is proccessing MORE information than classic raid frames are,
most raid frames have been optimized to not parse information for power bars, xpt for mana, and only sometimes. that and most raid frames only show your buffs or your dispellable debuffs.
I wouldn't reccomend PitBull for Raid Frames, hacking X-perl Raid Frames, sRaidFrames, Grid - would be preferable.
I had both solo hiccups in some locations (Netherwing Ledge among others) and 1-3 fps in 25mans.
My solution? Delete interface, wtf, cache, and start from scratch. I'm back up to the same list of addons I was using (150+ folders) with no problems. My guess is that there was some old configuration value somewhere in the WTF folder that was "off." By starting from scratch settings, reconfiguring my graphics/audio/etc., whatever the offending value was happened to have gone away/changed/who knows. I'd been using the same WTF "configs" since release.
Note: I did a full reformat and clean xp+drivers install (which had no effect) and then I went to 100% "vanilla" patched WoW and built back up.
Yes its a pain to set up all my addons again, but its a small price to pay to get my FPS back, kill the stutter, and be able to raid again.
edit: Skip the reformat thing, it doesn't do any good. I'd suggest nuking your WTF folder and running around in stutter areas with all your addons enabled but in disarray before you set everything back up.
I noticed on the PTR that inside Hyjal I would get massive amounts of lag during the waves of undead, but I don't think the number of mobs was the problem, I mean its a 25 man raid, I seem to remember massive AV battles being fine, and encounters like Razoregore in BWL where you had 40 people plus maybe 15 or so mobs up plus the boss with out any noticeable frame rate drops. So that blue post seems to confirm the FPS problems.