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Level 1

12 points

SOLVED: iMac 27'' (Late 2009) Poor Performance and Flash Issues w/ SOLUTION

I was able to cure all my performance issues by doing a low-level power/video/parameter reset (NVRAM/PRAM) to my iMac 27'' / 3.0Ghz / 4GB / ATi Radeon HD 4670 256MB

I had the following symptoms:

 Ridiculous boot time (5-6 minutes)
 Sluggish behavior in all window-based operations (hide/show/open apps; switch apps; open new windows, docs, etc.)
 Abhorrent Flash performance (even worse than usual for Flash)
 Xbench score = 124.22 (pathetic)

Steps to cure:

1) Shutdown iMac
2) Unplug power cord from back of iMac
3) Press and hold power button for 20 seconds
4) Restore power cord; power on iMac
5) Immediately on hearing Startup Chime, press and hold Command-Option-P-R keys (⌘⌥ P R)
6) Wait until you hear an additional four (4) chimes; the fourth (fifth) chime will (should) be louder and clearer
7) Release the keys and allow iMac to boot normally.
Note: This reboot may take up to two minutes, but subsequent reboots should be less than 30-45 seconds.

Results:
 Boot time 35 seconds
 super snappy app/window behavior (especially Parallels/Windows and Safari/Flash
 New Xbench Score = 286.24 (must admit I thought this would be higher)
 Super Happy owner of the hands-down, most kickass screen on the planet
HTH

Frederico

Message was edited by: Frederico

Mac Pro Quad 2.8/6GB/ATi HD 2600 x 3/ 5 LCD Displays, Mac OS X (10.6.1), iMac 27'' / 3.0Ghz / 4GB / ATi Radeon HD 4670 256MB

Posted on Oct 31, 2009 1:50 AM

32 replies

myhighway

Level 5

7,270 points

Nov 1, 2009 12:57 AM in response to good sam

+i'm only getting to the second chime... what gives?+

The key diagnostic for whether or not the reset has occurred is being able to notice the reset of the sound level to its default level. Unfortunately, such a difference can only be noticed by those who have previously adjusted their system sound level from its default position since their initial startup - I'm not sure how pervasive this is, although I'm sure I always adjust my sound preference as one of the group of about six preference settings I immediately change, even before proceeding with Software Updates.

Nov 1, 2009 2:18 AM in response to myhighway

unfortunately this was a temporary solution for me.

anybody tried doing a fresh install of snow leopard and see if it works?

Nov 1, 2009 6:44 AM in response to Sinan Uyar

I've tried the reset, and got all four chimes - no luck! After about 30 mins of iTunes music playing and a bit of Photoshop work, one of the cores acted up again, and I had to restart the computer.

The first thing I did, when I got my iMac 27" was to insert my retail Snow Leopard cd, I purchased back when it was released. I then updated it by Software Update.

I've had this iMac for 6 days now, and these are the problems I've encountered:

Flickering display
Topbar moved 2/3 of the screen down(2 times)
And major slowdowns - and not only with Flash but also with iTunes(When playing music)

The one things that goes again, is that is seems to come every time I use the graphic-card hard - like using Photoshop. But this might just be coincidence.

I've run an extended hardware test(Disc 2 Holding D) took about an hour, and returned no errors.

Hopes this answers some questions people have out there.

blort

Level 1

0 points

Nov 1, 2009 10:24 AM in response to jonashh_dk

Hi!

I've done some tests and it looks like either the wireless card is at fault, or the wireless driver.

If you're experiencing CPU spikes on one core after using your computer for a bit, try turning off AirPort, and then turning it back on. As soon as you turn off AirPort, the affected core goes back to normal.

A few things to think about: Your 27" iMac works _just fine_ until something happens in either the wireless card or in AirPort, at which point things slow down. This means that the hardware is capable of functioning properly, which means that it's most likely a driver issue that will be patched up soon.

Try running your iMac with AirPort turned off for a few hours, and see what happens.

Hope this helps =)

ai31

Level 1

0 points

Nov 1, 2009 11:07 AM in response to blort

Yes it definitely appears to have to do with AirPort. Turning it off and on does fix the Flash Player problem immediately. The CPU activity goes back to normal and all video works properly and the computer stops its performance issues. Now if we can get apple to release a fix for the problem it would be nice.

Nov 2, 2009 9:40 AM in response to myhighway

From what I have seen the following step will fix this issue temporarily - Flash video will play normally if you click on the AirPort menu extra and let it scan for networks.

This works for about 20 minutes to an hour. Once the issue starts again, repeat the scan for networks.

Best of luck. Let me hear how this works out for you.

Nov 2, 2009 2:33 PM in response to Frederico

I think I may have solved the iMac slowdown issues, check out my post here:

http://discussions.apple.com/thread.jspa?threadID=2220104&tstart=0

blort

Level 1

0 points

Nov 2, 2009 2:52 PM in response to laundry bleach

It looks like it may have something to do with the way AirPort uses certain routers for DNS. I changed my AirPort DNS settings to use OpenDNS's IP addresses (those are available at www.opendns.com), and the problem went away completely.

Let me know if this works for you.

GizaDog

Level 1

0 points

Nov 2, 2009 10:27 PM in response to blort

I changed my iMac DNS from 192.168.1.1 (airport router) to OpenDNS. This seemed to solve the performance issue. Interesting solution!

ktolani

Level 1

0 points

Nov 2, 2009 10:40 PM in response to GizaDog

how do u do tht?? do u just type "openDNS" on the dns box instead of 192.168.1.1? i mean im kinda new at these things. so i would appriciate if you could guide me.
thx

Message was edited by: ktolani

myhighway

Level 5

7,270 points

Nov 3, 2009 12:46 AM in response to ktolani

+guide me+

http://www.opendns.com/start/

http://www.opendns.com/support/article/251

I've never needed to use it, but I assume it's the "free plan" that they're referring to.

GizaDog

Level 1

0 points

Nov 3, 2009 6:48 AM in response to myhighway

I'm reporting back to say that I woke up this morning to the same issue after changing my DNS to OpenDNS. 😟

Nov 3, 2009 8:39 AM in response to GizaDog

I can also confirm that changing to OpenDNS won't fix anything, as I am always using OpenDNS, as I live in a country(Denmark) where the music/movie industry obviously has to much power, or has bribed the danish court.

blort

Level 1

0 points

Nov 3, 2009 9:07 AM in response to jonashh_dk

Does power-cycling AirPort still work for you, though?

GizaDog

Level 1

0 points

Nov 3, 2009 9:25 AM in response to blort

Using the Airport to search for wireless networks solves the issue temporally.

SOLVED: iMac 27'' (Late 2009) Poor Performance and Flash Issues w/ SOLUTION