Pc won't post depending on ram combination

[J328865]

So I recently tried overclocking my ram and cpu using a automatic overclock feature on my motherboard's bios called performance upgrade. I set it to 40% but the system wouldn't boot and it recovered back into bios. There is another automatic overclock feature on my board that just does the cpu, which I was using previously and had no issues with so I went back to that and turned off the other one. However I had a number of system stability issue and crashes after this. I turned off all overclocking, but I still crashed in games and had a few memory management BSOD. So I tried running memtest and got a large number of errors. I then tried testing each stick individually and only one gave back errors, stick 4.

I startsd testing all the different combinations and channels for my ram (I also updated my bios at the start of this). And all the results pointed back to stick 4 being the issue. I pulled it and put sticks 1 and 2 in so I could boot (it wouldn't post with 3 sticks in, I assume because my motherboard can't run a single channel while dual channel is in use?). However the system wouldn't post, even though it was with those two sticks earlier. It was stuck in a power cycle. I then tried other combinations to get it to post and here is what I have:

1and 2 together won't post in any channel.
1 and 3 post
1 and 4 post
2 and 3 post
2 and 4 post
3 and 4 post
1, 2, 3, and 4 won't post together anymore

Stick 4 remains to be the bad sick in memtest. However am I going to have to buy 2 replacement sticks now, as I have to replace 4, but also 1 or 2 as they won't post if they're together?

Any ideas as to why or how this started happening? At first I thought it maybe the bios update, but I tested 1 and 2 after that and it still posted then.

Pc:
Core i5 6600k
Gigabyte Z170 HD3 DDR3
Mushkin Silverline DDR3 1333 4x4gb
Asus Dual GTX 1060 6gb
Samsung 850 EVO 500gb
Thermaltake smart pro rgb 650w

 

[The Paladin]

your user manual for your motherboard is located at : https://www.manualslib.com/manual/977466/Gigabyte-Ga-Z170-Hd3.html?page=3#manual

the type of ram that will work on your system is the following type:

the order your ram has to be in is listed below , and your right if you are using a single stick you cannot use a pair of rams sticks
and vice versa so 3 stick is not possible no.

this is the layout of the board note the ram slots numbers this will permit you to properly insert them where they belong

 

[J328865]

Yeah I went through my user manual at the start to check which channels were 1 and 2. I've tried both channels when testing sticks 1 and 2, but still it no longer posts, and it also won't with all 4 correctly inserted.

 

[The Paladin]

one of two things possible

a) ram sticks are bad
b) motherboard is bad

attempts

1) try a cmos reset by removing the cmos battery and disconnecting power cord from wall and let it sit for 2 minutes then put battery back in motherboard and power it up, try to see if you get to bioe now.

2) swap ram with new or known ram that works (as in a friends) ;

a) try your ram on someone else's computer;
if it works its your motherboard;
if it fails then try if their ram is identical to yours you could confirm on your pc,
b) your ram doesn't work on your pc but works on their pc, but their ram still doesn't work on your pc;
your motherboard could have some chip die off on you.
replace motherboard

 

[J328865]

The motherboard seems to be fine. It will work and boot easily as long as I don't have sticks #1 and #2 both in at the same time. Using a combination of #1 and #3, #2 and #3, etc will work in either channel. How am I able to tell which is the bad one of the two, or which to replace, when they both work perfectly when used independently of each other? They come back with no errors on memtest. The only stick of ram that shows any errors is #4, which I already know for sure I'll have to replace.