Can I mix and match RAM?

[esefem]

I’ve been looking into upgrading my laptop from 4GB of RAM to 8GB. My Dad has an iMac with two empty RAM slots. Both of our computers currently have a 2x2GB RAM configuration. The RAM in my computer is a higher speed, but would it be possible to add my RAM to his? (effectively giving him 8GB in a 4x2GB config)

 

Thanks,

 

Bellow is more information of each of our RAM configurations (pulled from the Apple support pages)

 

Dad’s Mac

 

4 GB of RAM (1333 MHz PC3-10600 DDR3 SDRAM)

 

The maximum amount of RAM you can install in your computer is 16 GB (a 4 GB SO-DIMM in each slot).

You can use any Small-Outline dual inline memory modules (SO-DIMMS) that meet all of these criteria:

• PC3-10600
• Unbuffered
• Nonparity
• 204-pin
• 1333 MHz
• DDR3 SDRAM

You can use RAM module sizes of 2 GB or 4 GB in each slot. 

 

My Macbook

 

4 GB of RAM (1600 MHz DDR3L SDRAM PC3-12800)

 

• Double Data Rate Small Outline Dual Inline Memory Module (DDR3) format
• 67.6mm x 30mm (1.18 inch)
• 2 GB or 4 GB
• 204-pin
• PC3-12800 DDR3 1600 MHz type RAM

[toggleguy]

Just try it, I cant say for sure weather it will work. Nothing will likely get damaged.

[Egoist]

Yeah. But it will run at the lower speed of the the two kits. (Atleast that would be how it'd be on a Windows PC. No idea if the Mac would act up.) 

[Shally]

I'd love to know, keep up updated on how it  goes!

[zappian]

Sure just made sure you keep the same timings and speed.

 

Or dont.

 

It probably will work anyways.

 

I have mixed different speeds.

[JeffreyEagan]

I don't think they're the same size?

[gollum99]

 

-SNIP-

 

Sometimes, sometimes not... just try it!

[mapegl]

Usually this works and you can set RAM speeds in BIOS to match, or the mobo will just set everything to the same speed (which is likely).

 

BUT there is no guarantee it will work. Even identical pairs of RAM don't have to work with each other. of not verified by the manufacturer. This is very important to know. Getting two kits of the same, does not mean having 4 sticks that work with each other. Although it often works.

[Oberon.Smite]

Yeah. But it will run at the lower speed of the the two kits. (Atleast that would be how it'd be on a Windows PC. No idea if the Mac would act up.) 

It has nothing to do with the OS, just the MoBo and the BIOS itself. While the OS CAN regulate the RAM, it is the job of the MoBo.

[GuruMeditationError]

They might require different voltages. Try and find the voltage requirements for each, as you could potentially overload one.

 

Also, I don't know a lot about macs, but try and keep matched pairs to the same channel. i.e. if it's a duel channel motherboard (writes to and reads from the ram as two sets of two sticks) make sure they're paired up correctly.

[Egoist]

It has nothing to do with the OS, just the MoBo and the BIOS itself. While the OS CAN regulate the RAM, it is the job of the MoBo.

I was speculating. I have zero experience with OSX so I thought I add that part in brackets. 

[clementk]

hmm the only problem i see with that is that the one set is DDR3L and the other is DDR3 so might have a problem there but if there are all DDR3 it should work without a problem would just run a lowest speed.

[GuruMeditationError]

So maybe try and figure out if it's better to have more at a slower speed or less at a faster speed?

 

But do check the voltage?

[esefem]

Thanks so much for the responses. I plan to upgrade my RAM in about a week. I'll give it a try and let you guys know if it works.

[esefem]

Success!!!

 

I did the upgrade last week and it worked perfectly. My 1600MHz RAM under clocked to 1333MHz and now my dad has 8Gb of RAM