In Chrome, after I leave my tabs open and unattended to for a long time and click back on them, they appear blank for a few seconds before reappearing. Why does this happen? It's really annoying, is there any way to prevent this?
When programs aren't being actively used for a certain amount of time, the OS (assuming Windows) will write the data for the program that is saved in RAM to a portion of your HDD so the RAM is freed up for programs you are actively using. The delay you are experiencing is most likely the time it takes for your HDD to seek to the data and put it back into RAM.
Get more RAM or a faster HDD or turn off the paging file for the OS (but I'm not so sure that is a good idea).