Memory Riser Card on Mac Pro all of a sudden not showing up

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Level 2

245 points

Memory Riser Card on Mac Pro all of a sudden not showing up

I had to do a hard reboot of my Mac Pro this afternoon. Afterwards my memory riser card A doesn't show up or register. Before the hard reboot it did. Before the hard reboot all of my memory was just fine. I did have some trouble getting the right configuration to work originally but it's been working fine with 16GB. Now with 1 whole riser not showing up I'm down to 10GB on one riser.

Do I maybe need a new memory riser card?

Mac Pro, Mac OS X (10.7.1), ATI 5870

Posted on Aug 24, 2011 3:08 PM

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Answer 1

X423424X

Level 6

14,265 points

Aug 24, 2011 5:24 PM in response to Brent Austin

Look to see if there are any diagnostic leds lit near the dimm slots?

Perhaps try a smc and pram reset.

Also try removing the dimms and then reseating them in their dimm slots (in case of a possible flaky contact).

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Answer 2

Brent Austin Author

Level 2

245 points

Aug 24, 2011 8:24 PM in response to X423424X

Not only did that not work but now I'm stuck on an emergency boot partition which won't let me boot into my lion disk. Even on my emergency boot partition I only have 1 riser card working after resetting the pram and smc. It currently appears as if my whole Mac Pro with Lion just crapped out because I did a pram reset. I seriously don't know what to do. I'm going to try and see what I can do from a Lion DVD I made but it's starting to freak me out.

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Answer 3

X423424X

Level 6

14,265 points

Aug 24, 2011 9:27 PM in response to Brent Austin

It's beginning to sound like a hardware problem.

Do you have the original installer CD to see if you can even boot from that?

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Answer 4

Brent Austin Author

Level 2

245 points

Aug 24, 2011 9:33 PM in response to X423424X

I assume it has to do with the whole disk encryption I have enabled on my Lion hard drive. Resetting the pram must have disabled something from my Lion boot partition that I need. I will try to use my Lion DVD to hopefully fix it but I'm at work now.

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Answer 5

Brent Austin Author

Level 2

245 points

Aug 25, 2011 4:44 AM in response to X423424X

Well, I got my Lion drive back up, I just needed to use the DVD to boot from because the HDD was encrypted.

As far as my riser issue goes, the smc and pram reset didn't do me any good. I've taken the risers out and reset them twice to no avail. At this point I'm going to assume it's a bad riser. It's been flakey in the past, and nothing else explains why a hard reboot would cause a flakey riser to all of a sudden not be recognized unless that riser was just crap.

All my ram is fine, most of it is newer and has been working just fine.

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Answer 6

Brent Austin Author

Level 2

245 points

Aug 25, 2011 4:58 AM in response to X423424X

Well that's just weird, I switched the risers around and wigggled them in their slots to make sure they were good and set and now after switching them around all my ram registers.

Weird.

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Answer 7

X423424X

Level 6

14,265 points

Aug 25, 2011 12:17 PM in response to Brent Austin

Well one of my suggestions in my first reply was about reseating the dimms with the thought behind that being a possible flaky contact. I guess what you did was basically a similar operation.

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