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Slower Ram in L15 iMac

rawweb

macrumors 6502a
Original poster
Aug 7, 2015
935
645
I have 32gb of PC3-12800 1600MHz ram laying around from an older 2012 iMac. Will it work with my Late 2015 27? It requires PC3 14900 1867Mhz. Just wondering if I can use it while I wait to save up. Thanks!
 
Last edited:

drambuie

macrumors 6502a
Feb 16, 2010
751
0
PC3 (DDR3) SODIMMS will not fit in PC4 (DDR4) slots. DDR3 SODIMMS have 204 pins and DDR4 SODIMMS have 260 pins. Besides that, DDR4 runs at 1.2 volts vs 1.5 or 1.35 for DDR3.
 
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redheeler

macrumors 604
Oct 17, 2014
7,663
7,513
PC3 (DDR3) SODIMMS will not fit in PC4 (DDR4) slots. DDR3 SODIMMS have 204 pins and DDR4 SODIMMS have 260 pins. Besides that, DDR4 runs at 1.2 volts vs 1.5 or 1.35 for DDR3.
No current iMac takes DDR4 RAM, must be a typo in the OP's post. The late 2015 takes 1.35v 1867 MHz DDR3 (PC3L-14900) but slower 1600 MHz (or faster 2133 MHz) RAM should work fine.
 
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