(See below for my notes after the update)
After months of many 2009 Mac Pro owners (me included) posting notes and tests about this issue last November (I recorded over 110W increase just from playing audio alone in OS X (literally no load on the cores), vs literally none in Bootcamp/windows and others have noted other issues, including perf. impact), Apple's finally posted an update:
"Mac Pro Audio Update 1.0 (1.64MB)
This update is for Mac Pro (Early 2009) computers running Mac OS X v10.6.2. This update reduces processor utilization during audio activities, such as playing or recording music.
(BTW - for those that haven't followed this earlier, there's almost no load reported on the cores during audio only playback, yet a huge increase in wattage/power use seen in OS X - but not in Windows (or Linux).)
For detailed information on this update, please visit this website: http://support.apple.com/kb/HT4034
(Mac Pro: About Mac Pro Audio Update 1.0)
System Requirements: Mac OS X 10.6.2"
Hopefully this addresses the problem (w/o any negatives) although it wasn't just limited to Snow Leopard (I ran my tests in 10.5.8). Anyway, I'm sure owners in the apple forum thread from last November will be posting their results.
FYI: The About doc (linked above) mentions checking ASP after the update to verify AudioAUUC (extension) is v1.0. However my OS X 10.6.2 volume that hadn't been updated already showed v1.0 (w/late Nov 2009 last modified date) of that extension. (But I swear I didn't see it listed in ASP's extensions listing before the update - maybe it wasn't loading before this 'update' - so I checked using the Finder and took a screenshot of the Get Info window on it before the update. If anyone else checks that _before_ the update let me know if you see it listed in ASP's extensions. If it's not listed then it's not loaded.)
The update did apply and checking ASP's extensions after the reboot does show it listed - as v1.0 (and w/same last modified date as before the update. I can only assume that whatever change(s) they made - this extension is now being used/loaded now where it wasn't before.)
(Update - Noon Friday Marcel Bresink (author of OS X utilities like Hardware/Temperature monitor) wrote in reply to my comments above. See his comments with more details in Friday's news on What the 2009 Mac Pro Audio Update Really Changed. Regardless, I'm just glad my system is no longer ramping up 100W+ simply from playing audio in OS X.)
My Tests: I did a quick test after the Audio Update was applied (15min of audio only playback again, using onboard Audio) - my UPS' wattage meter shows almost no rise from audio-only playback (vs idle). As I mentioned in the article last year, previously I'd seen a 110W+ rise just from audio playback alone in OS X vs a few W in Bootcamp/Windows.
(FYI: A reader said the "Audio Update" also fixed the high wattage/high temps seen during Firewire transfers, but some Firewire audio interface users are reporting the "audio update" has caused a High pitch squeal when using Firewire audio devices.)
I wonder if they'll post a similar update for 10.5.8, which still has this issue with Audio (and Firewire transfers).
And maybe a future update will address the "kernel WARNING: ACPI_SMC_CtrlLoop::initCPUCtrlLoop - turbo enabled but no turbo P-state found" log entries I mentioned last year when booting OS X 10.6.2 - but I'd heard from a reader they're no longer seen in 10.6.3 beta. |
