Upgrading to 32GB in 27” iMac (2017 Model)

[idyll]

I am going to install 32GB ram in my 2017 27” iMac 5k 3.8Ghz i5.


Is it better if I keep the existing 8GB for a total of 40GB, or should I remove the existing memory?


If I keep the existing memory, is it preferable to install the new memory in any particular slots?


What is the best app to run to stress test my memory?

 

[DQ11]

I've heard it's best to have same memory type with same speeds and to slot them 1&3 or 2&4 if possible.

Or all slots if you need that many sticks.

Some others would know more than me though.

 

[mreg376]

I am going to install 32GB ram in my 2017 27” iMac 5k 3.8Ghz i5.


Is it better if I keep the existing 8GB for a total of 40GB, or should I remove the existing memory?


If I keep the existing memory, is it preferable to install the new memory in any particular slots?


What is the best app to run to stress test my memory?

Absolutely leave the 8GB right there. It's better to have 40GB than 8GB, and you paid a premium for those 8GB when you bought the machine. Just install the 2x16's in the two available slots. There are several testing apps out there, but if you bought quality RAM you don't have to worry about stressing it. Your iMac will tell you soon enough if it's not happy.

 

[SirApple]

I am going to install 32GB ram in my 2017 27” iMac 5k 3.8Ghz i5.


Is it better if I keep the existing 8GB for a total of 40GB, or should I remove the existing memory?


If I keep the existing memory, is it preferable to install the new memory in any particular slots?


What is the best app to run to stress test my memory?

Just out of curiosity, what RAM did you buy?

 

[mreg376]

I buy only one of two brands: Crucial's Mac-recommended RAM (currently $310 for 2x16 at Amazon for 2017 iMac) and OWC/macsales.com, currently $347 for 2x16. Over the years (including Windows and Mac) I have found them both equally excellent, they both have lifetime warranties that I have never had to use (OWC has an advance-replacement warranty) and when in the market I simply get the less expensive of the two at the time. That is not to say that you cannot find other spec-compatible quality RAM, but you cannot go wrong with either of these two.

 

[SirApple]

I buy only one of two brands: Crucial's Mac-recommended RAM (currently $310 for 2x16 at Amazon for 2017 iMac) and OWC/macsales.com, currently $347 for 2x16. Over the years (including Windows and Mac) I have found them both equally excellent, they both have lifetime warranties that I have never had to use (OWC has an advance-replacement warranty) and when in the market I simply get the less expensive of the two at the time. That is not to say that you cannot find other spec-compatible quality RAM, but you cannot go wrong with either of these two.

The reason why I ask is because I got 2x16gb from Crucial as a gift and they were not the ones that is suggested to you when you go on crucials website.

These: http://eu.crucial.com/eur/en/ct16g4sfd824a

I just got them this weekend but I haven't yet dared to use them, you think that it would be ok to use them?

 

[mreg376]

I took a look and they look like the exact same modules. It's likely that the only difference is that Crucial has part numbers that they actually test on Macs. But I don't see any reason that they would not be fine. And they were a gift. Put them in and enjoy. If the Mac boots up, you're good. If not, take them out. No harm done.

 

[SirApple]

I took a look and they look like the exact same modules. It's likely that the only difference is that Crucial has part numbers that they actually test on Macs. But I don't see any reason that they would not be fine. And they were a gift. Put them in and enjoy. If the Mac boots up, you're good. If not, take them out. No harm done.

Thank you

 

[idyll]

Just out of curiosity, what RAM did you buy?

I ended up getting OWC from Amazon, and have been getting kernel panics.

I tried various configurations, such as slots 1/3 and 2/4, with and without the original 8GB. Also ran the app Rember, which tests ram, and am getting errors.

I am going to try Crucial RAM from Amazon next.

 

[Brian Y]

I've got crucial in mine - 4 x 16GB (CT10559857) - and haven't had a single issue.

Paid £300 on eBay for 4 sticks, prices seem to have gone up (memory prices are mad) but you can still get 4 sticks for less than £400.

 

[mpConroe]

Man, that's crazy cheep for a memory.
I paid £276 for 2x16GB from Corsair and the first pair was faulty. I got it replaced and they work fine with stock 8GB RAM, which gives 40GB in total.

And judging for the activity monitor, system always takes at least 20GB when I work in Final Cut Pro X. I think it was a good investment, even for this crazy price.