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Phillie14586

macrumors member
Original poster
Oct 14, 2010
86
0
I have a 2010 single processor quad core so it only have one memory riser. Am I correct in that the memory needs to be installed as 3 of the same with nothing in the 4th slot or as one or two pairs? So 2x4G + 2x1G will work but 3x4G + 1x1G would not.
 

DeeEss

macrumors 6502a
Jan 17, 2011
642
181
As far as I know, everything works but 3 of the same, ie. triple matched memory works best. You can stick a 4th in and it will certainly help if you need that much, but 3 works best apparently.

For example 4x3gb (12gb) is faster that 2x8gb (16gb)
I read that 32gb is actually slower than 24gb, but if you need 32gb of RAM then it will stop the computer from being sluggish.
 

Stephen23

macrumors member
Jan 8, 2007
60
1
Austin, TX
The performance hit for using that 4th slot is only 2% - 3%, and that only applies if you're not actually using all of the available memory. If your system gets to the point that it's using all 24GB, then that 4th slot is going to help immensely.

Phillie - As far as I know, either of the examples you site should work, but you'll get far better performance if you stick with three of the same type, or if you need all four slots, four of the same type.

The sweet spots are 6GB (3x2GB), 12GB (3x4GB), and 24GB(3x8GB). If you use your machine like the average user, the best price/performance configuration right now is the 12GB. Paying for the 8GB sticks really only makes sense if you work with large files and use a lot of memory, or are pretty sure you will in the near future.
 

gpzjock

macrumors 6502a
May 4, 2009
798
33
Do you want frying with that sir?

I would recommend this RAM instead: http://www.memoryamerica.com/dk3512721333au.html
It has the Apple recommended heatsinks on it to help prevent overheating memory. My RAM runs at 70-80ºc at peak use with the heatsinks on and over the last 3 years I have had to RMA replacement RAM that has failed. Fortunately the vendor supplies a lifetime warranty so it only costs me shipping.
 

johnnymg

macrumors 65816
Nov 16, 2008
1,318
7
I would recommend this RAM instead: http://www.memoryamerica.com/dk3512721333au.html
It has the Apple recommended heatsinks on it to help prevent overheating memory. My RAM runs at 70-80ºc at peak use with the heatsinks on and over the last 3 years I have had to RMA replacement RAM that has failed. Fortunately the vendor supplies a lifetime warranty so it only costs me shipping.

My 2010 MP came with "naked" mem modules so I guess Apple doesn't use that recommendation.

cheers
JohnG
 

gpzjock

macrumors 6502a
May 4, 2009
798
33
Interesting, how are your temps? I suspect they have improved the cooling in that case. :)
 

johnnymg

macrumors 65816
Nov 16, 2008
1,318
7
Interesting, how are your temps? I suspect they have improved the cooling in that case. :)

25-28 C with a room temp of ~18 C. This is for the replacement 4x4GB modules.

FWIW, the Northbridge temp is 35 C.

regards
JohnG
 

diazj3

macrumors 6502a
Jan 19, 2008
879
135
It has the Apple recommended heatsinks on it to help prevent overheating memory. My RAM runs at 70-80ºc at peak use with the heatsinks on...

70-80ºc ram?!? isn't that way too high, even at peak use?... I'd recommend you either check your machine, or install other RAM just to check it's not defective and the thermal sensors are working properly.... just my 2 cents.

The price difference between different RAM brands/vendors is so marginal - specially with large amounts - that I'd rather go with OWC. I like their mac focus and customer service.

cheers!
 

gullySn0wCat

macrumors 6502
Dec 7, 2010
396
0
The heat spreader recommendation doesn't apply to 2010 Mac Pro because they don't use FBDIMMs.

70-80 degrees under load is still within the correct operating temp for the kind of memory in older Mac Pros. I usually get 60+ in slot a1 (it has worse airflow) then 50-60 idle in the other slots, which usually goes up to 70 under load.

My Northbridge temperature is 65 now. LOL!
 

Phillie14586

macrumors member
Original poster
Oct 14, 2010
86
0
Thanks for the replies. I do Lightroom, iMovie and use the computer as a home theater recording and playing recorded TV. It came with 3x1G so I was thinking of going with 2x4G and use 2 of the 1G sticks for a total of 10G. If I go to 3x4G and not use one of the 1G sticks then it is about $75 for those last 2G. My break point is $75 for 3G but that would mean using the 3x4G then a 1G stick in the fourth slot. So I was wondering if I take a hit for running dual channel and another hit since one pair would not be matched or would it run as triple channel plus 1 stick?
 

gpzjock

macrumors 6502a
May 4, 2009
798
33
Nice to see they fixed the airflow.

Thanks for the temp info Johnny, it would appear that Apple have vastly improved the airflow round the memory boards and switching from FBDIMMs has reduced the heat generation significantly.
I assume the change was an evolutionary process and the improvement in temp has helped with the RAM failure rate. :)

I'd go with 3x4gig tbh, screw the expense.
 
Last edited:

Vylen

macrumors 65816
Jun 3, 2010
1,026
0
Sydney, Australia
Thanks for the temp info Johnny, it would appear that Apple have vastly improved the airflow round the memory boards and switching from FBDIMMs has reduced the heat generation significantly.
I assume the change was an evolutionary process and the improvement in temp has helped with the RAM failure rate. :)

I suppose so... since Nehalem (2009), they did away with the riser cards and now the CPU and RAM are on the same daughterboard. Consequently, airflow doesn't go from the front, through the CPU heatsinks, then the riser cards and out the back on the FBDIMM systems. Instead, air goes past the CPU and RAM simultaneously... as so to describe it.
 
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