Serious Lion Lagging on 27" iMac

[powerhouse7]

Hi,
I've now had lion for a few weeks now and don't particularly like it, but regardless, every now and then when I boot up into Lion my system seems to have a freak out and the below issues occur:

1. RAM usage goes from the usual 5 GB of free RAM (out of 8 GB) to 750 MB
2. Sound doesn't work
3. All system animations (everything from the dock scrolling to opening applications) are EXTREMELY laggy (I assume this is related to RAM)
4. Startup and shutdown take 3 - 4 times longer than normal
5. Upon startup, the system brings up the login window instead of the normal automatic login that I have set

Also, when this does happen, I get this at startup:

So far, I've tried resetting the PRAM, NVRAM, SMC, and running a full maintenance/clean with Onyx.

Can anyone explain this weird occurrence?
Any help would be much appreciated!

PS: I apologise is this thread has been posted elsewhere, I haven't come across one quite like this though.

 

[maflynn]

That progress bar at boot up is an indication that you may have some issues with your hard drive.

Here's the apple KB article on that and also a TAUW article

Given that you're dealing with some serious latency issues and you see that progress bar at boot up, check your hard drive for errors in Disk Utility.

 

[powerhouse7]

Thanks for the reply and the links!

I've now verified both the startup HD, its mac osx partition, as well as the secondary HD and everything is coming up fine?

I'm covered by Applecare and I backup regularly so I guess its just a case of don't force a shutdown during startup and hope the problem goes away.

Interestingly, a few times this has happened and, frustrated, I've forced a shutdown then rebooted immediately. The problem doesn't occur a second time and its booted in a matter a 10 seconds.

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Do you think reformatting the hard drive and reinstalling the OS will fix the issue? I just find it odd that this issue only occurs under Lion, making me wonder if its a software issue?

 

[eneisch]

Did you upgrade to Lion from Sonw Leopard or do a clean install. I upgraded on my MacBook and had alot of of little issues, especially slowdowns.

Backed everything up and did a clean install of Lion and I have been much happier with the performance!

 

[powerhouse7]

I upgraded. I'll do a clean install and hope all my problems go away. haha.

I'll use a Lion Install Disk I made from the download installer and see how I go, or can do a fresh install from the Backup Partition?

 

[eneisch]

I used the install disk I created from the download installer. I think that is the better method.

 

[randolorian]

I went to the AS last weekend to checkout the 27" iMac. The full-screen animations in Lion were just terrible -- choppy and blocky. My 2008 iMac and MacBook Pro perform much better under Lion.

I found the same graphic perf problems on the 21" iMac. however, the new macbook airs were smooth.

I guess there is a video driver issue on the iMacs. they need to sort it out soon because i'm sure it's not impressing potential buyers.

 

[pbrooks]

I have a 2011 27" iMac. No problems here.

 

[powerhouse7]

Once I reinstall the OS from the DVD, will doing a Time Machine restore be ok, or will that defeat the purpose of reinstalling from scratch? Would it be better to manually copy over all my personal data and settings instead?

If it weren't for Mail, I'd downgrade back to Snow Leopard in a second.