75 degrees is ok. You won't see errors - assuming you are overclocking, you are just watching temps and checking that the system is stable.
The 920 will automatically shut down around 105 degrees. As a rule of thumb I would aim to keep temps at load under 85 degrees.
Image editing: 1459 points. Video encoding: 2823 points. Multitasking testing: 1275 points. Overall score: 1852 points. is my score why some like multitask so low?
Did you turn hyperthreading off? The scores do look a bit on the low side. Are you running CPU-Z to confirm the CPU frequency?
i would recommend strongly that you read on here how to overclock theres tons of information just search for it. Will be so much easier for you aswell.