Also, make sure your refresh rate is set to the correct Hertz.
Agreed. I usually set mine to 85 Hz, this gets it far enough away from the standard light that the screen won't flicker or "flucuate". Of course, any setting will do, this is just my personal preference.
Let's try to take the graphics card out of the loop. Can you replace it with another one? If not, does your motherboard have onboard video, so you can plug your monitor directly into your motherboard? Try that, this way, if you still get the artifacting, you know it's your monitor and not your gfx card. Although, I believe in safe mode, it doesn't load the drivers for the graphics card, so that should be ok....but you never know if just running through the card is enough to screw it up
Have you tried using a different monitor on your computer? Have you tried putting your gfx card in another computer to see if it duplicates the problem?
You can also try taking out 2 of your case fans, and leaving just one fan. Only run the machine for a few minutes this way (don't want it to overheat, but that would take more than a few minutes). See if the artifacting goes away. If it does, you might want to consider replacing your power supply with something of a higher wattage and a higher amperage on the +12v line.
Also, (and this goes for all the time, not just this instance), ensure that your psu (power supply unit) is getting a clean feed, meaning that the line that goes from the psu to the gfx card does not
have anything else on it. I've had this happen to me before, I got a new gfx card and had issues, and come to find out it was the psu that was the cause...it wasn't "big enough" to run it along with my 3 case fans, 2 of wich were LED including a 120mm LED
Hope this helps! Let us know!