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Can 4850 iMac owners help find the cause of the freezing? Is it WiFi?

jebiwan said:
I've tried to reproduce the problem playing four movies at the same time from Safari, and couldn't hang the computer. Then, I was posting my recent tests and it freezed again.

This only proves that it's difficult to hang the iMac purposely.

The only thing I know so far is that my iMac only freezes if I connect to internet via wifi. If I disconnect the wifi, it works perfect for hours. That includes playing games and watching movies so I don't think it is a heat problem.

I don't know if it is a hardware or software problem but I would bet that it is not a heat problem.

By now I bet for the wifi problem until someone tell me otherwise.
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Im running a GPU test at the moment - if it doesnt crash in the next 2 hours, im going agree with you :)

(in windows, disabled wifi running gpu stress test)
 
So it seems that WiFi may just be the issue. I now want to see if disabling WiFI on failing iMacs will resolve the issue, or if enabling WiFi on so-called "working" iMac would break them. If so, then I will try and formulate a test which will try and gather info about the differences in the WiFi cards between working and failing iMacs.
 
Me doing tests too :)

So far 3 HD(1080p) trailers looping with safari & wifi -> Freezes @ 5 min

5 HD trailers looping without wifi -> so far 25 min no freezes

Trailers running in Quicktime

Configuration 2,93GHz 640 GB

If in an hour I do not become a freeze I would do a Opengl test with the 5 HD trailers running.

I will keep you informed :D
 
This is getting interesting. Wifi might be the problem.

As I mentioned in other thread, my iMac hasn't frozen since Saturday, and the only change I made is to tweak my wireless router to manually assign IP to the iMac. I'd suggest people do the same see if your iMac still freezes.
 
GamaFu said:
This is getting interesting. Wifi might be the problem.

As I mentioned in other thread, my iMac hasn't frozen since Saturday, and the only change I made is to tweak my wireless router to manually assign IP to the iMac. I'd suggest people do the same see if your iMac still freezes.
Click to expand...

Interesting. I'll wait until people complete the current WiFi test. I may then test your theory if the WiFi theory survives the testing. Thanks for the info! :)
 
Just recieved mine a couple hours ago, and so far it's perfect :D

I'm connected via ethernet; I had wifi on initially but have disabled it.

So far all I've been able to do is watch a little streaming tv and run the iTunes visualizer. All good so far.

I'm installing WoW now; I'll put the machine through its paces in the next couple days and update if needed.

Good luck to everyone!!!
 
Yup, 3 freezes with wifi on - Saturday and Sunday. I am actually connected via ethernet however, so I killed the wifi on Sunday pm, been going for about 8 hours since then, doing various things - WoW, Word, Safari, EyeTV, often simultaneously across two monitors - no freezes.

Could it really be this simple? :)
 
Poisednoise said:
Yup, 3 freezes with wifi on - Saturday and Sunday. I am actually connected via ethernet however, so I killed the wifi on Sunday pm, been going for about 8 hours since then, doing various things - WoW, Word, Safari, EyeTV, often simultaneously across two monitors - no freezes.

Could it really be this simple? :)
Click to expand...

1 hour 40 minutes stress testing, no wifi.....no problems - looks like it!


i have a replacement imac on order, if it's just wifi do i risk getting a screen with dead pixels :) ?
 
GonzoRob said:
1 hour 40 minutes stress testing, no wifi.....no problems - looks like it!


i have a replacement imac on order, if it's just wifi do i risk getting a screen with dead pixels :) ?
Click to expand...

Well, no WIFI means no Time Capsule and that's what I was going to buy next ....
 
flopticalcube said:
Not necessarily. You could hook up via ethernet to the TC until a fix is found.

This got very interesting very quickly. Good work people.
Click to expand...

Well, let's hope my imac crashes! been testing 15 minutes with wifi (no crash)

If it lasts 2 hours (like my previous test without wifi) i think it might be something different...
 
Wifi isnt the problem. My ATI-4850-iMac freezes even with no connection to any network. Dont hope for a replacement. I got a second iMac today and after only one hour the same problem occurs. The first one even froze when started from DVD.
 
But do you have wifi ON? I wasn't connected via wifi, but had it on, and I had freezes. Since I turned it off, no problems. So far....
 
fjaekel said:
Wifi isnt the problem. My ATI-4850-iMac freezes even with no connection to any network. Dont hope for a replacement. I got a second iMac today and after only one hour the same problem occurs. The first one even froze when started from DVD.
Click to expand...

send it back again!

If people are still getting freezes even with the card disabled, we may have to find another case.

so far it's not freezing with wifi on .... which is just confusing! if it's not wifi, god knows what it is!!
 
Of course its turned off. Sorry
But why sould it freeze when started from DVD if its a WiFi issue? Its definitly the ATI.
 
fjaekel said:
Of course its turned off. Sorry
But why sould it freeze when started from DVD if its a WiFi issue? Its definitly the ATI.
Click to expand...

I dont know if it is... ive been stress testing the GPU for over 2 hours in windows (no wifi) and another 30 minutes (with wifi)

So far, the freezes never seem to be during 3d stuff ...
 
GonzoRob said:
send it back again!

If people are still getting freezes even with the card disabled, we may have to find another case.

so far it's not freezing with wifi on .... which is just confusing! if it's not wifi, god knows what it is!!
Click to expand...

Why should I? To get another freezing iMac? Maybe I will give it ONE more try but if it doesnt work then I will give it back and wait for the problem to be fixed to buy it again. Downgrading makes no sence for me since i bought it mainly for an improved GPU.

"So far, the freezes never seem to be during 3d stuff ..."
Isnt the GPU working all the time? Why do only people with ATI cards see the problem?
But anyway I have the feeling that it crashes more often and faster when in games or watching videos.
 
GonzoRob said:
I have a freezing imac, if it is the wifi then this test should prove it ...
Click to expand...

Well good luck but I got a bad presentiment. By the way it just crashed once playing Colin McRae Rally and watching a movie and the first one twice playing Empire at War.
 
first 1080p Trailer... Freeze (enabled wifi, inet via wifi)
8 1080p Trailers... no Freeze (disabled wifi, inet via ethernet)
reactivated wifi for the 9th Trailer... Freeze at the end of the Trailer

is it possible that there's a difference in the AirPort Cards?
 
Macole said:
Let's chek the model of the airport cards so .
Click to expand...

and compare them to what? a different model iMac like the 130? 120? 8800? or maybe a different Mac altogether?

It doesn't seem like anyone with the 4850 that hasn't been freezing has been using WiFi so what would be the point of comparing the airport cards unless someone with a non freezing 4850 reports that they have been using WIFI.
 
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