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MP 1,1-5,1 Installing Apple Heatsinks on Non-Apple RAM for 3,1

mgbt

macrumors newbie
Original poster
Aug 9, 2019
6
0
UK
I've got a Mac Pro 3,1 that I'm going to use as a Plex server. It came with 16Gb of RAM, pulled from an HP server, with slim, non-Apple heatsinks on the 667MHz RAM. It works fine and has had no issue. Everything I've read has lead me to believe that I need the bigger heatsinks to avoid heat issues later on.

I bought 64Gb of 667MHz RAM for £38 on eBay. It came with the same slim, non-Apple heatsinks.

I also bought cheap Apple RAM with the giant heatsinks on it with the intention of pulling the heatsinks to install on the 64GB of RAM.

I've googled it, but have no idea how to do this. How complicated is it? What tools and supplies do I need?
 

Sko

macrumors 6502
Oct 17, 2009
285
59
Germany
I've never had any luck fitting large heatsinks on standard RAM. There was always a small gap either between heatsink and RAM or heatsink and AMB. So I decided to put a tiny heatsink above the AMB. Job done.

See my original post in another thread.
 
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mgbt

macrumors newbie
Original poster
Aug 9, 2019
6
0
UK
I've never had any luck fitting large heatsinks on standard RAM. There was always a small gap either between heatsink and RAM or heatsink and AMB. So I decided to put a tiny heatsink above the AMB. Job done.

See my original post in another thread.

Thanks for the quick reply.

I'm not familiar with the term "AMB" and didn't have success in googling it. Sorry. What does it mean?

I wish I'd clocked your post before I bought the Apple RAM. Is there no way to bridge that little gap between the AMB and/or RAM? Nothing thermally conductive I could use to do it? I'd rather not end up wasting the heatsinks I just bought :(
 
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Sko

macrumors 6502
Oct 17, 2009
285
59
Germany
AMB = Advanced Memory Buffer, an extra chip on FB-DIMMs. But have a go with the large heatsinks, maybe you are lucky and it fits. Have thermal pads with various thickness ready.
 
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mgbt

macrumors newbie
Original poster
Aug 9, 2019
6
0
UK
Thanks again for your quick reply. It never occurred to me to look at the Wikipedia page for FB-DIMMs.

I've done some googling and came across thermal pads of various thicknesses. Any idea if those cut to size might make the heatsinks sit snugly?
 
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Sko

macrumors 6502
Oct 17, 2009
285
59
Germany
I guess you could make it fit, the gaps are in the 1 mm range.

Be aware that the temperatures are kind of high anyway, so don't bother if your are already around 70°C. And give all fans, the CPU heatsinks and the PSU a good clean with compressed air, just make sure that the fans don't move when you blow lots of air through them, hold them tight (correct term?).
 
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Sko

macrumors 6502
Oct 17, 2009
285
59
Germany
I've googled it, but have no idea how to do this. How complicated is it? What tools and supplies do I need?
I just realized I never answered your original question: it's easy. A middle sized flathead screwdriver (or some other device that could be used as a lever) and some respect for the task ahead should be sufficient.
 
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mgbt

macrumors newbie
Original poster
Aug 9, 2019
6
0
UK
Thanks for clarifying about the installation of the heatsinks. Sounds easy enough if I take care. I'd expected there to be some kind of gotcha I didn't know about.

My plan is to clean it properly, install the RAM, and run it for a while before doing any work on it; hopefully it won't be needed. Good advice on the fan.

Is that a 1mm gap on each side of the FB-DIMM inside the Apple heatsink, or 1mm in total (0.5mm each side)? Last question -- honest! I just need to know whether to order 1mm thick, or 0.5mm thick thermal pad.
 
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Sko

macrumors 6502
Oct 17, 2009
285
59
Germany
I experienced about 1 mm on each side, the geometry you'll face might be different. The only way to be sure is to disassemble and see what you got.

Keep 'em questions coming...
 
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Macschrauber

macrumors 6502a
Dec 27, 2015
993
366
Germany
Ive done that quite some times. I keep all dead ram sticks with large heatsink. So I have a lot of them. Some fit, some not.
 
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mgbt

macrumors newbie
Original poster
Aug 9, 2019
6
0
UK
Thanks for the replies. I'll try it out when I get the RAM and report back.
 
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alexffff

macrumors member
Aug 26, 2017
43
9
Ive done that quite some times. I keep all dead ram sticks with large heatsink. So I have a lot of them. Some fit, some not.
@Macschrauber, what did you do with the locks located on the sides? They are of different widths.
2020-03-29 01.35.11.jpg

I think it's not safe to cut the board.
The only way I see is to bend up locks and apply heatsinks without using locks.

Thanks for the replies. I'll try it out when I get the RAM and report back.
@mgbt, do you have any news?
 
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