I have this: KHX1600C9S3P1K2/8G 2x4GB 1600MHz CL9 kit and am having problems with my laptop. Let's call each of the sticks in the kit RAM1 and RAM2. I also have four slots in my laptop let's call them slot1, slot2, slot3, and slot4.
When I run Memtest86+ v4.20 with a SINGLE stick in "each" slot there are no errors for around 8-9 passes.
When I run with BOTH sticks either in slot1/slot3 or slot2/slot4 configuration, I get errors.
I don't think the slots are defective because they run properly with a SINGLE stick.
I also noticed a weird thin in Memtest86+ v4.20. When I run a SINGLE stick either inserted in slot1 or slot3, the program reports 9-9-9-27 but when I run it inserted in slot2 or slot4 the report is 6-6-6-20. The weird thing is that in both cases, CPU-Z in Windows indicates SPD info of 9-9-9-27 which is the expected behavior since this is what's specified in the JEDEC ratings for 1600 MHz.
Hoping for your comments on this. Thank you very much.