Etrecheck says my new SSD is slow on 2007 iMac; screen freezes except pointer
I've installed a brand new Crucial BX500 240GB SSD on my friend's 20" mid 2007 iMac after her original hard drive failed. I clean installed El Capitan. All updates have been completed. Sometimes after a few minutes the screen freezes except for the pointer, which is still moveable, but unable to click on anything. I ran Etrecheck and it didn't come up with much other than that the SSD was showing poor performance. However, when it works, it's actually quite smooth and speedy, and works flawlessly in Safe Mode. Trim is enabled. I have upgraded the RAM to 4GB, but the issue is the same with the original 2GB RAM too. The issue was not present with the previous standard drive. Any ideas?