Small box printing time preview too long in creality print (40 hours...)

Ender Series Creality Ender-3 V3 KE/SE
1

Hi,

I’m new in3d printing, so i’m doing some tests and printing my first objects.
i use thingiverse to download STL, but some of them (according with the preview)takes 35 or 40 hours to be printed, and other (almost equal) just 40 minutes. i’m printing small boxes for some esphome circuit, is nothing complicated,

the question is, why two object that only differs in maybe one hole, can be so different in the preview printing time?
am i doing something wrong? maybe not all the STL can be printed with creality print?

thanks in advance

2

Which slicing program for starters? At present I am mostly using Creality Print 4.8.3 and noted a simple model this afternoon on 0.2mm setting it would 1.5 hour but on 0.15mm setting it went up to 30 hours. I had set ironing in 0.15mm to get a better top layer but not in 0.2mm. Other settings to check is how much infill, the higher the percent the longer the print.