New iMac 27" freezing

Probably. Try switching to the original ram and you'll find out

Take the ram out that you added and see if it freezes. That will tell you if it is the ram.

Have to agree with the above posters, just a couple of days ago there was a User here having problems with Corsair 2 X 4 GB memory, exchanged it with another set, also Corsair but different type and again problems.

where did you get this ram from?...when i run search all i get is hp notebook...

I stay away from corsair ram when it comes to macs, great for pc but not so much for Macs in my experiance. Grab some crucial ram and see how it goes.

Just read the other RAM thread. The corsair RAM is CL 10 whereas the Apple RAM is CL 11. That's probably causing the trouble. I'm curious if someone with the Crucial CL 11 RAM is experiencing similar problems.

Using 2 8GB Ram modules from Crucial alongside the 8GB Apple Ram sticks and not experiencing any issues whatsoever.

boto said:

Using 2 8GB Ram modules from Crucial alongside the 8GB Apple Ram sticks and not experiencing any issues whatsoever.

Click to expand...

Thank you. i'll sleep better tonight
@OP: just See if you can sell your RAM or send it back...?

bugbear99 said:

i got it from a local store.

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i have already remove the Apple stock ram, but still freezing.
i guess it's because the ram spec which is not so compatible to this iMac
the corsair ram run 1.5v
the stock ram run 1.35

i wish i was go for crucial.

is anyone using this ram and haven't any issue?

Click to expand...

Other people are using the Corsair without issue... Try maybe 2 sticks and see what happens..

Have been using Kingston RAM for 3 generations of iMac, works like a charm

bugbear99 said:

Just arrived yesterday, freezing for 3 times.

3.4G
680mx
1TB fusion
using corsair vengeance 16G kits (8x2) CMSX16GX3M2A1600CL

it's occasionally freezing when loading / opening app
when freezing, mouse pointer still can move
temperate is low (fan at low speed)
cpu is low as well

hardware test found nothing

is it because the ram?

Click to expand...

So you are actually using 16gb of the original ram AND 16 gb of the corsair ram for a total of 32gb?

Yikes, I also have 16 GB (2x8) of Corsair Vengeance DD3 modules lying around, waiting for the iMac to arrive. It's CMSX16GX3M2A1600C10 to it seems to be exactly the same modules as yours...

So do Macs need special memory modules (apart from standard specs such as SODIMM, DD3, 1600 MHz) because of the voltage?

Yeah, I see special 'Apple' RAM from Transcend, Mushkin and Corsair (CMSA16GX3M2A1600C11) so that seems to point to a compatibility issue...

Had 32GB of the Corsair on order (Crucial's out of stock of the recommended modules for the 27" at the mo), but I canceled that earlier today after seeing these posts. I'll wait for Crucial to restock, I think. Better safe than sorry...

I ordered the same stuff yesterday. I was just reading the Amazon reviews and there are several saying it works great in various Apple products. I'll be trying 1 pair in my 17" MBP tomorrow night.

Did you sit the original Apple and CORSAIR memory modules properly?

Mac is pikky on ram, use Hynix or Samsung chipset to be safe.

Have to say, shoddiest service ever received from an Internet retailer with Crucial.

I ordered the recommended ram, paid Paypal and went through and I got the order confirmation.

5 days later I heard nothing, so checked the account to see the order was cancelled.

No email explanation, nothing. Terrible service. I emailed them yesterday complaining but over 24 hours later no reply. The ram is now out of stock.

Terrible. I am in the UK and would like to source an alternative supplier.

Run Rember which is a memory tester for Mac OS X....it will tell you if you have a bad stick. I had one in the Corsair Vengeance Kit for my Mac Mini Server...replaced it and all was well.

bugbear99 said:

i'm using only corsair ram for a total of 16GB.

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i removed the corsair ram, and install back the apple ram.
no freezing for 6 hours so far
i'll try to install corsair once again to confirm the source of the problem.

Click to expand...

Did you make sure to install the RAM in slot 1 and 3, or 2 and 4? They should be staggered for correct pairing.

I'm not sure if it has to do with the OWC ram in this case, but I have to RMA my imac. It crashes to grey screen on startup sometimes. Can't hold on to a firewire adapter signal and killed my mouse and is just unstable. I re-ordered a replacement and now I'm thinking I should have got Apple Ram to be safe? Obviously huge price difference though.

Is there some foolproof way to test this 3rd party ram while in the imac?