The only way we can reproduce the cycling is if the computer overheats or another application like a web browser is active.
If you cannot hear your fans then your computer probably has a problem.
For the constant stuttering/spikes that some people are describing, we need more information how to reproduce this. We can reproduce it at the moment but it never last and it will stabilize really fast.
17" Macbook Pro, Intel 2.53ghz Core i5, 4 gigz 1067mhz DDR3, Intel HD & Nvidia GT330m graphics (CUDA Driver Version: 4.2.7, GPU Driver Version: 126.96.36.199 (256.00.35f11)), and OSX 10.6.8, running a 32-bit kernel. I've posted full system specs elsewhere in the thread, I think with my druid Avantgarden as my avatar. I'd post them again, but I feel that this is already gonna be rather longish; for that, I apologize :_(
As I mentioned earlier in the thread, Machkhan's dealy-O of matching the in-game resolution to my comp's resolution seems to have fixed the issue....for the moment, anyways.
I'll detail my experiences here, and try to semi-organize it so that it's clear. Hopefully this stuff will be of use to others, as well as the Mac team.From Release through pre-1.02b:
Initially pretty playable at release @ 1920x1200 (also my desktop res at the time) with everything maxed except Shadows, which were off; the foreground framerate was capped at 150. I was getting framerates somewhere in the ~40 range, plus or minus a few depending on what was going on in game. Perhaps a few days later - generally low framerates and some mild cycling, with occasional spurts of playability. This held true throughout every resolution, every graphics setting, multiple d3prefs, multiple graphics drivers, SMC/PRAM resets, purging inactive memory, force quitting Agent, deleting Cache and Agent.db files, closing all processes except those that are essential, reboots/shutdowns, both 32 and 64-bit kernels, factory restorations.....essentially, everything ^_^ Various programs being opened or closed seemed to have no effect on the game, both during low fps and playable times. At the time, I had no way to monitor temp readings, so nothing to report on that front.1.02b through Present:
I was able to play @ 1920x1200, with the settings I was using upon Release, with fps capped @ 25, for about 2-3 hours....it was glorious <3 After that, however, the insane cycling began, going from 25 fps down to 8-10, back up to 25, etc. Again, with occasional periods of normal playability. Also across various graphical settings. It was at this time that I downloaded the SMC fan control app. Conducting all troubleshooting procedures as I had pre-1.02b yielded no noticeable difference. At various points in the troubleshooting process, monitoring temps along the way, I'd make a note of what changes I had made and the temps that I was seeing with them. The temperature spread was quite small, ranging anywhere from 77 up to 82 degrees Celsius during both the cycling AND the periods of playability, regardless of what other processes were or were not running in the background. It was at this time that I noticed whenever I put D3 in the background, windowed; brought another app to the foreground, waited a few minutes, and then made D3 my active window again it would play fine for a few minutes....only for the problem to return a few minutes later.
Which brings us to the present, and Machkhan's phix. 1280x800 resolution on the desktop, with the in-game res to match, all settings on High, V-sync off, Shadows off, and fps capped @ 25. Framerate holds steady at ~25, regardless of what apps/processes are running in the background. What this means as to the cause of the problem, I have no idea. Temps are still in the 77-82 degrees Celsius range during gameplay. If anything changes, I will be sure to update this post. If y'all have any questions or need more info, please ask.......I have pages of it. I hope this wall of crap is useful to you guys :3
TL;DR: Temps stayed the same regardless of resolution/playability, so I'm not sure heat was an issue, at least not in my case. But while it may not work at every resolution, as I have not tried them (I'm afraid to change anything now X_x), changing both desktop and in-game resolutions to 1280x800 fixed my problem....YMMV. Good luck!