That board doens't have a lot of the overclocking features of many of the higher-end boards including manual vCore adjustment & lack of power phase.

You might wanna go through THIS GUIDE for more overclocking tips on this board.

Although the CPU is 2600K, basically can be applied on 3770K as well.

Could be memory issues. Did you overclock your RAM?
Don't do it at the moment. Check out your BSOD the nvlddmkm.sys is related to nVidia graphic card.
You should update your graphic card driver.
Besides that insufficient vCore also might cause the BSOD, try upping vCore to 1.35-1.4v, if your cooling still allow.

Glad to hear that you managed to get rid of that BSOD. Hopefully the current settings serve you well. So I think it's due to insufficient vCore.
The FSB:DRAM = 1.1 most stable is not true and baseless especially when you're dealing with integrated memory controller (IMC) built on the current architecture.
After looking at some of my rigs, with BCLK (FSB) 100, these are what CPU-Z shows for FSB:DRAM; 1:9, 1:10, 1:11, 1:13, 1:14. The biggest factor has a lot to do with what the CPU's IMC can support & handle those RAM frequencies.
To cut a long story short: My advice is to get the best RAM and CPU one can get to get the best performance. And don't mind no ratios.

No, any Ivy chip can easily hit 5.0GHz, with proper cooling of course.
And your BSOD is caused by insufficient vCore again.
So pump more juice to it.

You better stop at 4.7 or 4.6. Run some stress tests posted in Post #1.
Good luck 

Memory/RAM related.
Could you pls show us your BIOS settings especially the voltages & timings.

Since it's memory related issue you could try to bump up DRAM voltage (vdimm)
Obviously timing is referring to DRAM timing control in your picture.

1.5v
9-9-9-24
Command rate 2N

Let the subtimings set to auto.

On stress test as long as it's below TJMax 105C then you should be fine because in daily routine works you will not hit this kind of temp.

There are several ways to reduce the heat/temp:
Upgrade to a better air cooler/fans or watercooling etc if got budget
Reapply a better thermal paste
decrease vCore
decrease CPU PLL voltage
Buy a case with better airflow
If you dont mind to void Intel warranty, delid the internal heat spreader (IHS)
Etc....

i hope that it's a typo.

This fan might fulfil your needs:
Nexus PWM Series D12SL-12PWM 120mm

Not sure if it's available locally but you can always order from newegg MY.

can check out NB Multiframes. They have a PWM version which hits 2k rpm, I think. APES has them locally.

here you go

source

the PWM version is not listed, but they have. I was in their store today.

Assuming that your RAM is not OCed. Try adding vCore.

Different chip different VID thus different vCore.
Try increasing notch by notch until pass.

You might want to try increasing the VCCIO a little bit. I increased mine in most of my OC.

4.5Ghz for 1.45v, yours must be the worst chip. 
Should be something else which is causing the error. It could be voltage (VCCIO, vDRAM/vdimm) or RAM timing.
Suggest to run MemTest to ensure that your RAM functions & is set correctly.
You are going to figure out on how to run the test.