Recently I swapped my laptop's hard drive with a brand new one since the old one was failing. I didn't restore from any backup so I just used the Win10 installation media to install a brand new OS onto my new hard drive, then simply dragged over my important files from the old drive.

Afterwards I noticed that I'm no longer able to edit relative large files (1-10mb, probably not considered large at all for devs) with long overflowing lines with notepad++. Every time I scroll anywhere near sections of the file with very long lines, the fps would drop to like 0.1 making scrolling almost impossible. At first I thought it was a notepad++ problem, so I installed the trial of UltraEdit, but exact same problem. Both were working perfectly fine before I swapped hard drives.

Is this an issue with my computer or something? It's highly unlikely both programs suddenly fails to edit any text file with overflowing lines. I even reverted to older versions of notepad++, still the same problem. Neither program is using the GPU (I have Nvidia Optimus on this laptop) to open.

Edit: just did a test. The moment a single character overflows the edge of the screen (horizontal) requiring scrolling, the program would slow down significantly for that section of the text. The more it overflows (eg, 1000+ characters on one line), the slower it is. Scrolling past that section of the text with lots of overflow would get the program back running full speed.

Edit 2: changing the encoding to Western European iso8859-1 seems to make the performance slightly better (like maybe 0.2fps instead of 0.1fps...) but nowhere near the performance before I swapped hard drives. Also I'm pretty sure the encoding was always UTF8 on my old hard drive.