My iMac (mid-2010) had 2x 2 GB RAM, the other two slots were still open. I decided to add 1x 4GB of RAM, 8 total, and I put it in the right slots (2+2, 4+0, this was the only way to get it working). It starts up normally and the RAM is recognized, but after a couple of minutes it reboots with the message "Your computer restarted because of a problem.". I double checked and while the RAM isn't official, the specs are the same. Any ideas what I can do? I thought I might need another 4 GB to pair it with, but it should be working like this and I don't want to spent more money on not-working memory cards if that's the problem.