Where to buy RAM?

iMac 5K, late 2015, 4,0

This is my third run with 2x16gb RAM from OWC. This is the third time they crash. I don't want another replacement. The last time I returned the 2x16gb, they told me the sticks were fine, but they failed to tell me how they tested them. Since iMac works fine with 2x4gb from Apple, there must be something wrong with the sticks from OWC. I want to try 4x8gb. Someone tells me it's more stable then 2x16gb.

So, any other place the OWC?

I get mine from crucial.com they have UK and US sites.

You're double posting your issues here, which is frowned upon, BTW.

The stick could be fine, it could be something on the motherboard failing to handle that much physical RAM. Could be corrupted OS. Many of us have used OWC RAM for decades and their reputation is very good. If they tell me a RAM card is good, I believe them.

As I said on your original post in the FCP thread, take that machine in to an Apple retail store to be checked out. Could be something RAM related, that isn't the RAM itself. I've seen that happen more than a couple of times. Happened to me on an old Mac once.

Crucial or Kingston gets my vote.

I might try 8x4gb. If this doesn't work, I will have Apple to look at it.