help! intel iMac + new 1GB RAM = display problems

governor

macrumors member
Original poster
Aug 31, 2006
33
0
Sweden
Hi!

I recently got my intel imac 20" with 128mb vram..

i thougt 512mb of ram was to little, so i installed a 1GB stick of Twinmos 5300 667mhz (the recommended)

It worked fine for one day. then suddenly i started to experiance some issues with my display. a small hair-thin (about one pixel thin) darker line occured on the horizontally from top to bottom of the display. (about one inch from the left side of the screen)

i tried a variaty of things.. when i switched places with the ram-sticks the problems was gone for an hour tops.. Then it occured.. again!

So i took out the new 1gb stick of ram, and kept the original (512mb) in.. This seems to solve the problem.. (has been working all night now without issues) So my question is: Can a faulty RAM-stick cause display issues? Everything else worked fine, and the computer did work wery well except for this.. Shouldn't a faulty ram (non matching for my computer) get errors and artefacts directly from the start when i put it in??

Has anyone here experienced these kind of troubles?
 

HungrySeacow

macrumors regular
Jan 11, 2006
137
1
West Palm Beach
governor said:
Hi!

I recently got my intel imac 20" with 128mb vram..

i thougt 512mb of ram was to little, so i installed a 1GB stick of Twinmos 5300 667mhz (the recommended)

It worked fine for one day. then suddenly i started to experiance some issues with my display. a small hair-thin (about one pixel thin) darker line occured on the horizontally from top to bottom of the display. (about one inch from the left side of the screen)

i tried a variaty of things.. when i switched places with the ram-sticks the problems was gone for an hour tops.. Then it occured.. again!

So i took out the new 1gb stick of ram, and kept the original (512mb) in.. This seems to solve the problem.. (has been working all night now without issues) So my question is: Can a faulty RAM-stick cause display issues? Everything else worked fine, and the computer did work wery well except for this.. Shouldn't a faulty ram (non matching for my computer) get errors and artefacts directly from the start when i put it in??

Has anyone here experienced these kind of troubles?
I would suspect that you have a faulty video card. Try using the original ram for a day or two and see if it doesn't happen. Even so, the iMac does not share system ram with the video system. My very first iMac had a bad video card and would do something similar once in a while. Viewing iPhoto slideshows caused it more often.
 

governor

macrumors member
Original poster
Aug 31, 2006
33
0
Sweden
HungrySeacow said:
I would suspect that you have a faulty video card. Try using the original ram for a day or two and see if it doesn't happen. Even so, the iMac does not share system ram with the video system. My very first iMac had a bad video card and would do something similar once in a while. Viewing iPhoto slideshows caused it more often.
But if it is a faulty video card, why then does the problem it dissappear when i remove the 1gb stick?

Ive been running the computer for about 4-5 hours now.. I ran Front Row, Movie Trailers, slideshows of iphoto in front row, and a several other demanding applications.. So what you are saying is that faulty system RAM can't cause display issues?
 

orangezorki

macrumors 6502a
Aug 30, 2006
618
17
This may be something more physical - maybe a bad connection or some debris inside the panel, which moves when you turn the machine upside down to install/remove the DIMMS.
 

governor

macrumors member
Original poster
Aug 31, 2006
33
0
Sweden
HungrySeacow said:
With the aftermarket RAM, how long does it usually take before the problem happens?
EDIT: Also, where did you purchase the RAM?
Usually about an hour.. I can't really tell. I got the computer new from applestore 2 weeks ago, and i installed the 1GB stick about 24h before the issue occured, and was there even if i restarted the computer. Then shut the computer down (note: not in rest), and went out for lunch. Over one hour later i came back, switched on the computer, and the problem was still there.

I shut it down .. again.. Pulled the powercord, and switched places with the two memories. The issues then dissapeared. After about an hour they occured again!. Then i did the same procedure again, but this time i kept only the original 512mb RAM stick in the front side memory bank. The issues dissappeared!

The display now shows no signs at all of the problem. And ive been keeping it running for about five hours now without any issues..

Now how could that possibly have to with a faulty videocard // GPU ? :/


I bought the ram from a local shop in my country (sweden)

http://www.scandinavianphoto.se/?601127
 

governor

macrumors member
Original poster
Aug 31, 2006
33
0
Sweden
Ok.. The ploblems came back again, after the computer was running for a several hours more. It is a faulty video card. This is how it looks like.

http://img160.imageshack.us/img160/3175/displayissueab3.jpg

Lucky me, apple support was very supportive for once, and a brand new imac is allready on its way to my place with the TNT delivery service. Then i'm hopefully also finally gettin rid of the annoying dead pixel in the upper right, and the loudy superdrive :)