Installing 1866 Mhz RAM on a 1333 Mhz limit Mobo

Hmm Neil seems to me to make common sense that if the mobo is limited to support 1333 then stick in (no pun) what speed RAM you like in whatever config you like and it will not go any faster than 1333 because even if the RAM tries to clock itself it cannot go any faster than the mobo will allow / support.

In fact it might be causing the problems you are experiencing now two things you can do is a memtest https://www.sevenforums.com/tutorials/105647-ram-test-memtest86.html - just make sure you run for at least 8 PASSESand check with the mobo's site for compatible RAM plus there is always some good advice from Tradesman at here http://www.gskill.us/forum/ he will advise you on what you can run on your mobo.

Now the other outside possibility is the mobo is going south and it may be the slots and not the sticks so if you do the memtest and it comes back with errors then you will need to test stick 1 in slot 1 and then slot 2 and do vice versa with stick 2 - slot 1 then slot 2. Depending on the outcome you will be able to pinpoint the errant stick or slot because if the sticks are good then ant errors will therefore have to be the slots.

To be honest even if your board supported more than 1333 I don't think for the day to day stuff you would notice that much difference if any at all. I run an Ivy Bridge RAM which is defaulted to 1333 and even clocking it at 2400 I cannot tell there is any difference at all.

Your mobo is only rated at 4 GB of RAM. That is all it will support.

To get your new RAM to run at 1866, you could try the following:

Keep in mind that this could damage your motherboard, or CPU, or your RAM.

1. Set your new RAM at 1333
2. Lower the multiplier on your CPU in BIOS
3. Increase your system clock speed in BIOS so that your RAM is set at as close to 1866 as you can get
4. Adjust the CPU multiplier so that the CPU speed is as close to stock as possible
5. Save and exit BIOS. Reboot.
6. Run Memtest86+ for 8 passes to confirm the RAM is working.

This probably won't work though. If the mobo has a hard limit of 4GB, then it probably only has a max slot addressing limit of 2 GB per slot, which is why the machine crashes when you booted it with only one 4 GB stick in place.

It might be time for a new motherboard.

Yes I think you are right time for..... As Mellon Head and I have suggested a memtest would not go amiss but I think that even if it came up with errors something is amiss with the sticks or board slots.