2011 mbp ram in 2009 imac?

[Treeman574]

I am planning to upgrade my 2011 macbook pro to 8gb of ram in the near future. I don't want the extra memory to go to waste, so I'm wondering if it is compatible with my family's early 2009 2.66GHz core 2 duo imac.

So far the only difference I can find is that the mbp has 1333mhz, PC3-10600 ram and the imac has 1066mhz, PC3-8500 ram.

Will this ram just be limited by the hardware, but otherwise function normally? Or is the new ram completely incompatible? The imac currently has 2gb, so bumping that up to 4gb would be a nice improvement.

 

[dgbowers]

I'm pretty sure they're not compatible. (not entirely sure though) My main concern would be that since the new stuff is a good bit faster, it may fry the board.

 

[vancleef]

From what I can see it would be compatible. When you install faster RAM than supported, it doesn't fry the logic board or anything, it just runs at supported speed. And both the iMac and MBP uses SO-DIMM sticks and therefore it will fit.

 

[Dalton63841]

From what I can see it would be compatible. When you install faster RAM than supported, it doesn't fry the logic board or anything, it just runs at supported speed. And both the iMac and MBP uses SO-DIMM sticks and therefore it will fit.

This. If it will boot with that ram, it will be downclocked to the appropriate speed.

 

[Treeman574]

Okay, it does appear to work. Showing 4gb of 1067mhz ram in system profiler. So far no problems!

 

[CHSeifert]

I'm pretty sure they're not compatible. (not entirely sure though) My main concern would be that since the new stuff is a good bit faster, it may fry the board.

NO !

Faster ram NEVER fries a mother board as long as the other specs are matching. The faster ram just downscales to the speed which the motherboard, CPU and chipset supports. So it will work just fine !

 

[drambuie]

Actually, 1066MHz is the default speed for DDR3 SODIMMS. If a system BIOS, or EFI can use 1333MHz, and that value is in the RAM's info header, then it will run at 1333MHz, using the RAM timings for that speed. If either the system, or the RAM is only 1066MHz capable, it will run at 1066MHz.

Running at 1066MHz isn't as bad as it sounds. At 1066MHz the RAM will run with 7-7-7-20 timings, but at 1333MHz it will run at the slower 9-9-9-24, or 9-9-9-27 timings. If you have access to the BIOS, or EFI settings, the timing for 1333MHz RAM can be changed to 7-7-7-20, but system stability will depend on the quality of the RAM. The problem is that most laptops and all in ones don't easily allow such BIOS or EFI changes.