Hello, I'm having issues with my iMac (27', late 2009), and after some troubleshooting still can't figure it out so I thought I'd ask here.
So, if you have one or two Rams installed in your computer then take out all of your computer’s Rams from the motherboard and then place only one ram into the slot just for the testing purpose and then test your PC.
- To test this, you’ll need to open your PC, take out a stick of RAM, then switch the PC back on to see if it works normally. Keep doing this until your PC malfunctions again. When it does, try putting the RAM stick you took out in place of another RAM stick (leaving its original slot empty).
- You have already isolated the cause to one specific DIMM socket. Although mechanical damage of these sockets is difficult, closely inspect the internal pins. You may require a Jewelers' Loupe, although I don't expect that you will find physical da.
The first time I noticed a problem was when I booted up a couple of days ago. The screen had random pixels transplanted all over the place, and if I attempt to perform simple tasks such as moving windows or simply clicking on icons, the system freezes up -- when that happens I can still move the mouse pointer around but that's all I can really do, and have to hard shut down.
I then tried using the CD with the Apple Hardware Test (i.e. together with holding 'D' key down while starting up), and it revealed the following error code --
4MEM/9/40000000: 0xb78df418
Upon researching this error code, it appeared that it was pointing to my RAM as a potential issue. I thus proceeded with the following steps --
1) removed and re-inserted the 4 RAM cards (no difference in symptoms)
2) removed 1 RAM card one-by-one and tried starting up (to see if any 1 of the RAM cards was faulty, but no difference in symptoms)
3) tried starting p with just 1 or 2 RAM cards in certain RAM slot configurations
#3 above is where it got interesting. I found that if either 1 or both of the back pair of RAM slots were used, and the front pair left empty, I would get 1 beep every 5 seconds upon starting up. If I just use 1 back and 1 front slot, the rig starts up fine, but still with the pixels. According to this, that's telling me the back pair of RAM slots is bad? The thing that confuses me is that when I only use the front pair of slots, I still get the pixels. So do I have a pair of bad RAM slots, and 4 bad RAM cards too? Is it possible for bad RAM slots to cause all RAM cards (even those in good RAM slots) to fail?
iMac, OS X Mavericks (10.9.3)
How To Check For Bad Ram Slots
Posted on
Bad memory can cause an assortment of different issues on your computer. Below are a few of the possible issues you may encounter. It is important to remember that the below issues can also be caused by more than bad memory.
- Computer does not boot, and you are getting a beep code. See the POST and beep code page for additional information about them.
- Random computer crashes causing BSOD, General Protection Fault error messages, Illegal Operations, Fatal Exceptions, etc.
- Random computer reboots.
- Windows or another program installation failure.
Before testing your memory, if you have recently added any new memory into the computer, we suggest you temporarily remove it to make sure it's not the cause of your issue.
Software
Several software programs available that are designed to test your computer's hardware, including the computer's memory:
- Windows Vista, Windows 7, and Windows 10 have a Windows Memory Diagnostics Tool that can be accessed by clicking on the Start Orb and typing 'memory' in the run line. Running this command opens the Memory Diagnostics Tool with two options: 'Restart now and check for problems' or 'Check for problems the next time I start my computer.' Choosing either of these options runs the computer through a memory test the next time it starts up.
- Memtest86 - Our recommendation for testing computer memory, Memtest86 is an x86 compatible, free memory tester.
- DocMemory - Another great software solution to test the status of your computer's memory.
Below is a listing of some other great products for you to check out.
- Memory testers - Companies offer different hardware solution for testing computer memory. These are the highest quality methods for testing memory, but likely only to be used at a computer service center because of their cost.
- PC-doctor - A fantastic, but not cheap solution often used by service centers and technicians to diagnose computer hardware issues including memory issues.
- PC Diagnostics - A company that offers both hardware and software solutions for testing the majority of computer hardware in your computer, including memory.
- Ultra-X - A great collection of products that can help test computer hardware, including memory.
Swap and remove memory
If you have access to compatible memory from another computer, you can swap that memory into your computer to see if it's the issue. Using memory known to be functional in a computer that may have a memory problem is a good method of checking.
Bad Ram Slot
If your memory works in another computer without issues, you're likely encountering a motherboard, power supply, or other hardware issue.
Replace memory
If you have found the memory to be bad, we suggest replacing the memory with new memory. Additional information and buying tips on computer memory is on our memory buying tips page.
Which Ram Slots To Use
Additional information
- See the RAM definition for further information and related links.