Internal HDDs Cannot Be Accessed For Small Intervals Of Time

I have 4 internal HDDs and have had this setup for about 2 months now. I had to reformat my computer this week and have since been having a problem with my hard drives. While I am browsing folders and occasionally even using programs, my HDDs will seize up for around 5-10 seconds. One of the drives starts to make some loading noises and then eventually they begin to work again. While this is happening I can usually use the GUI that is loaded and most things loaded into RAM, however I cannot access the HDD for anything new.One of the internal drives was originally an external drive, the Seagate FreeAgent 500GB. I suspect it may be the culprit here. I was having this exact same problem before with it; whenever I'd plug it in through USB, even if accessing another drive, I'd have the computer seize up and have to wait for it to finish making similar sounding loading noises. Removing it from the case and plugging it in internally fixed the issue completely, until I reformatted this week. I have checked all the cache options for the drives and they are all set the same; default which is just the top option checked off. I did this as I suspected that the Seagate drive is set with the same cache options as it did when external, but it's not the case.