Help me Overclock

Any over clocking you do to the cpu, or the graphics card will require more power consumption or draw from the power supply unit in your system.

If the current power supply unit is the bare minimum the system requires without over clocking then you should not attempt to over clock things.

Find out what the maximum power consumption of the cpu is in wattage drawn from the power supply unit of the system.
And also find out what the maximum power consumption of the graphics card is.

Check on the power supply how many amps the 12v power rails can provide, as over clocking requires more amps as much as more wattage draw from the PSU.

When you over clock a cpu, as well as changing the cpu multiplier value in the bios if the cpu has an unlocked multiplier say for example by 200mhz, you also have to increase the core voltage of the cpu.

So it remains stable, increasing the frequency in Mhz a cpu works, or operates at, requires more power to keep it stable at the running frequency.

And increase to the cpu core in small Mv or Millivolt steps is required.
Starting with adding an extra 0.250Mv to 0.500Mv to the core.

You must pay attention to how hot the cpu is getting when doing this, particularly when the cpu is put under any kind of cpu intensive task.

And you must also check what the maximum cpu core voltage can be set for the cpu, and not go over the stated voltage setting.

Over clocking does not always work, or improve the clock speed, or performance of a device over clocked.
In fact if you push a over clock to high it negatively effects performance.

The 40Mhz increase in steps is too much you should be doing it at 10Mhz.
Then testing the system.

Then upping by another 10Mhz.
And when dealing with the graphics card you focus on the gpu core speed first in small steps.
Until you reach a maximum where it is still stable under a heavy load, testing.
Once happy.

You move on to tuning the memory of the card and it`s clock frequency.
You never adjust both at the same time when over clocking a graphics card, each one is done in small step increments at a time.

That way you know what the cause is of the system crashing, and do not have to guess if it is the gpu core over clocked too much, or the memory of the card.