Late 2015 iMac 27 seems to run 2133MHz RAM

[Jeremy A-H]

I just upgraded the memory on my late 2015 iMac from 8GB to 32GB and to future proof myself a little against having to replace them again in a year or so, I bought 4 x 2133 MHz HyperX modules from Kingston. After inserting the new chips, I was somewhat surprised to see:

'Your Mac contains 4 memory slots, each of which accepts a 2133 MHz DDR3 memory module'.

I'm not sure whether this means they are actually running at the increased speed, but it would be an interesting fact if they are.

PS As a side note: in normal use, the new iMac seems to use around 60% of the power of the late 2014 iMac. Not sure that'll contribute much towards the cost of the next upgrade, but I'm happy with the reduction in power consumption nonetheless!

 

[keysofanxiety]

I just upgraded the memory on my late 2015 iMac from 8GB to 32GB and to future proof myself a little against having to replace them again in a year or so, I bought 4 x 2133 MHz HyperX modules from Kingston. After inserting the new chips, I was somewhat surprised to see:

'Your Mac contains 4 memory slots, each of which accepts a 2133 MHz DDR3 memory module'.

I'm not sure whether this means they are actually running at the increased speed, but it would be an interesting fact if they are.

PS As a side note: in normal use, the new iMac seems to use around 60% of the power of the late 2014 iMac. Not sure that'll contribute much towards the cost of the next upgrade, but I'm happy with the reduction in power consumption nonetheless!

If you click Apple menu > About this Mac, what is the RAM speed listed please?

 

[Jeremy A-H]

It is showing 'Memory 32 GB 2133 MHz DDR3'.

Incidentally, I thought it might be worth testing with Geekbench 3 (64 bit) which is showing memory speeds are up between 8% and 15% (depending on the test) over a comparative 4GHz machine with 64GB 1867MHz RAM and up 30% (pretty much across the board) for a machine with 8GB 1867 RAM.

If anyone's interested: http://browser.primatelabs.com/geekbench3/compare/4133697?baseline=4139975

 

[twilexia]

Yes, it is well known that the latest iMac accepts the 2133 Mhz speed DDR3 RAM.

 

[kødskjold]

Yep, seems to be working for some folks that posted in this thread: https://forums.macrumors.com/threads/2133mhz-ram-test-results.1929801/

 

[Jeremy A-H]

I knew it would take them, but I wasn't aware that it actually took advantage of the additional speed. I hadn't seen the 2133MHz thread, but glad it works as well as it does

 

[whodatrr]

I only had my 5k briefly, but had to return it for hardware issues. When I ran geek bench and so on, I'm guesstimating I got about a 3% performance bump. Take this with a grain of salt, because the system was new and there weren't many similar results to compare it to, but that seems to be in the ballpark of people's experience. Not an earth-shaking improvement, but not a costly on either, since I'd estimate my 32 GB of 2133 RAM cost about $30 more than 1867 that I could find.

 

[xgman]

The newest macbook pros seem to be able to run at this speed as well.

 

[Jeremy A-H]

For me, the cost was the same as ordering the 1867MHz chips, so it became a no-brainer to try it out!

 

[Jeremy A-H]

The newest macbook pros seem to be able to run at this speed as well.

I thought the latest Macbook Pros had the RAM soldered on to the mainboard? There's no obvious way into mine without unscrewing a load of screws on the back.