boot - Does Ubuntu 16.04 64 bit support 2 different RAM sticks with different speeds?

I have a very strange issue in running Ubuntu 16.04, 64 bit on my Dell Inspiron N5110, Bios version is A11.

Initially, the ram was 3gb (speed 1333)i.e 2gb + 1gb. I found the computer to be slow and so decided to upgrade the ram. I bought Corsair 8gb (speed 1600) ram.

So I installed the new ram by removing 1gb stick. The computer booted into both Ubuntu and Windows 7 (dual boot setup) properly. No issues. But when I tried to boot into Ubuntu the third time, the kernel went into panic and my capslock key was blinking. Sometimes, the screen would turn grey with no progress. I want to mention that I am able to boot into Windows 7 with no problem and even into Recovery menu of Ubuntu (i.e. Advanced boot options of Ubuntu).

Since addition of the RAM was the only last change I made, I removed the 8gb stick and it booted fine with 2gb stick in it. Then I tried to keep only 8gb and it booted fine. But when I tried to boot 3rd time, it again goes into kernel panic or grey screen. This time, I inserted the 2gb stick back again along with the 8gb stick already present. Voila, it booted fine. But just for 2 times. The third time, it again starts Capslock key blinking which means Kernel panic.

After observing this problem for sometime, I have concluded that the system needs changes in RAM configuration to boot fine once it goes into kernel panic.

E.g.
a) If I am on 8gb+2gb and the issue starts then I will just remove
either the 8gb stick or 2gb stick and it will boot fine for 2-3
times.

b) If I am on 8gb stick and the issue starts, I will simply add the other stick and it will boot fine.

The problem doesn't occur when only the 2gb stick that came with the laptop is present. As suggested, I have done memtest of both the rams and they have passed all tests i.e. no errors from memtest.

I am not sure what is causing this problem. Is it possible to resolve this problem? I am definitely sure the cause of the problem lies in have a ram with different speed i.e. 1600 Mhz rather than the one recommend i.e. 1333 Mhz. But what puzzles me is that the issue occurs only after two successful boots, the third time Ubuntu goes into kernel panic (Capslock key blinking or only grey sceen present).