How to tell Memory Riser A & B apart (2008 MP)

[fridgeymonster3]

I took my early 2008 Mac Pro apart this afternoon to do my annual cleaning and to do some upgrades (see pic). I removed both memory risers without remembering which riser was A and which was B. In the past, if I put the riser back in the opposite way, my Mac Pro refuses to start. I'd rather not have to futz around with the memory risers, can someone tell me how to distinguish the risers from each other?

 

[PowerPCMacMan]

Hi, having owned an 08 Mac Pro myself the boards are identical. It does not matter which one is A or B, as both are the same. I suppose you could take a sharpie and write an A for one, B for the other. Just be sure you don't write on a contact.

Best to write it off to the side, near the copyright dates.

 

[paulrbeers]

My 2006 doesn't care. I assume if it mattered Apple would have differentiated the boards... They are smart like that.

 

[snberk103]

I have the 2008 8 core, and recently needed to swap the A & B risers to diagnose a memory problem. My system didn't care which riser went where.

If your's is being finicky then you may have a bad one. At one point I thought I needed a new one, and found out that they were surprisingly cheap. The store (Apple authorized, not an Apple store) quoted me $100 Canadian for a replacement. Luckily I didn't need it. And by "cheap" I mean by Apple's standards...

 

[thehimay]

The risers are dictated/named by the ports on the logic board itself. In the current layout you have shown:
'Riser A' is the upper (towards the PCIe slots) riser card slot.
'Riser B' is the lower (towards the case bottom) riser card slot.

 

[Snowshiro]

The risers are dictated/named by the ports on the logic board itself. In the current layout you have shown:
'Riser A' is the upper (towards the PCIe slots) riser card slot.
'Riser B' is the lower (towards the case bottom) riser card slot.

Excactly that. The actual boards that hold the memory are identical. If you slide the board into the top slot, it becomes Riser A. If you slot it into the bottom slot it becomes Riser B. Which way you do it doesn't matter (unless something is faulty).

 

[pprior]

Wow, I just spray compressed air around in there. Way too much work, imo.

And it doesn't matter - they're the same.

 

[Phrygian]

i have an early 2008 as well and it is very dusty.... I haven't had the guts to take off the front fan unit.

and you got quite a lot of storage on that, kudos

 

[fridgeymonster3]

Thanks for the replies. I thought the Memory boards were interchangeable, I just had a problem one time that was solved by swapping the boards. I didn't have any problem last night when I started my MP back up.