After fixing vram I get extremely bad screen tear when I boot up, help?

So I fixed my vram recently so I have 1536mb of vram instead of only 7mb and now when I boot up the apple logo and loading bar disappear for a second a little over halfway through the boot and then my screen splits into like 12 different vertical lines that all show the same area of the screen and it's extremely distorted.

The only temporary fix I've found is to press my computers power button so my screen turns off (I think that's sleep mode?) then turn the screen back on again, then my screen will be fine until my next bootup as far as I'm aware. Can someone help me find a permanent solution? I have a Dell Inspiron 5558 laptop and I'm running High Sierra.

submitted by /u/eRa_Tension
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