NEW09 imac External Monitor causes mouse to freeze every 4 sec for half sec

I have the exact problem with my November 21" iMac. My display is a LG.

Today i reattached my 24" Screen again and voila the problem is gone.


Common apple there has to be a solution.

@buliwyf

Did you do anything special that you can recall? Install anything? Was the iMac off when you plugged in the other monitor, or was it on?

What type of monitor / connection cable are you using?

Thanks.

No the Mac was powered on an showed the Desktop with several apps.
Then i plugged in my Mini-Display Port to DVI adapter.
The display was recognized and everything was fine again.

My external display is a 24" Dell.

I contacted the Apple support and they said they had other reports of iMac owners having trouble with their LG displays. The girl I was talking to advised me to contact LG in order to see if they had any driver upgrades for my screen. Since my screen is pretty old I didn't find any drivers for it online and I didn't even bother to contact LG.
I also tried hooking up a 24" Dell display and that one worked like a charm.

Due to the fact that my Screen (Dell 24") worked for nearly two month with the iMAC and before that several month at another Mac i highly doubt that the problem is the externel screen or the driver.

I have the same problem. When I connect my imac 11.1 I7 to my Samsung LCD via mini display port to DVI, mouse start frezzing. I also try, to use my wired Logitech G5 mouse, but the problem continue.

Hope apple solve this problem soon...

I'm having the exact same issues with my early 09 24" iMac 3.06 Ati 4850 running 10.6.2. The moment I connect a second monitor (Asus 19") the machine will consistently freeze for half a second every four seconds or so. The exact same setup; cable, adapter and monitor works perfectly on my sister's current model white macbook.

I've narrowed it down to the SystemUIServer process, which spikes in time with the freezing. I Haven't yet contacted support as I thought there would have been a fix on the forums. No chance.

Apple, expect a call from me in the morning.

@iMocan did you contact support?

I did and off the bat spoke with a senior-level tech ... nice enough, but he had not heard of the problem, and could not find the problem in their notes. Later that day he had me run a program which creates logs while it was happening -- which I did and sent back... the next day he simply said he forwarded it up the line...

That was Monday -- it's now Friday and that tech has not replied to my last email earlier today. sigh

HATE this...

I have the same issue with my Viewsonic monitor and my MB unibody.

I received an email today (Sunday?) from my tech contact, who was nice enough to reply to my email Friday asking for a status update... it simply read

"You know, I did get a response over the weekend. You available tomorrow? What time would be a good time for us to connect?"

In which I said : Now is great! .. but I'm not at the office. So hopefully I'll get a call from him tomorrow around 11:00am EST. I'll certainly keep everyone posted.

I have already posted this in a different thread. My father is experiencing similar issues with a 27" iMac and a 19" external Sony display, which worked well before. Did all the tests like different mouse, starting from system disc etc. tech support told him the display might be too old... not really the answer we were looking for, especially since the display worked fine on his previous iMac.

Let's hope there will be a system update to fix this.

Any further word from Apple on this?

I just got my Apple Cinema Display working (faulty power adapter)and it works fine as a second monitor on my 27" iMac unlike every other monitor I've tried which has the "mouse stutter"

Okay, I've been doing some more research on this issue as I now have a new i7 of my own with this issue.

I'm using a Sun 24" monitor connected via DVI and I get the stutter. If I connect the same monitor using the analog cable, no problems. The one thing that caught my attention today was that I decided to drill through the monitor's menu to see if there was anything I could change to make the problem go away. The info screen showed that HDCP was enabled. Hmm... connected via analog and HDCP doesn't even show up in the menu. So, an HDCP session will result in the exchange of keys between the source and display device and I wonder if this exchange is caught in a loop (or maybe that's just how it works).

As far as I can tell there is no way, either in my monitor or on the iMac, to disable HDCP. I wonder if those who have gotten their second, DVI connected monitors to work are using HDCP compatible monitors.

Thoughts?

Another thought just popped into my head. If, in fact;

A. It is HDCP causing the issue
B. We need to strip out the HDCP handshake

Then, would introducing a non-HDCP compliant device (such as a DVI switch box) into the mix work? Kind of a pricey solution to try but it would be worth every penny if I could get this 24" monitor working with no mouse stutter.