if it really just happens with games, that's it. Simple or not depending on how ya think. Games get annoying. Sure we want them to look sweet but they tend to make us buy really new hardware...lol
I believe the only real lagger is hard drives. They increased the capacity, reduced the price per gb...and THEN focused on transfer rates. What type of interface is your harddrive, any variant of SATA?
Depending on your game, if it uses compressed textures, they will often uncrompress via HD then pass it off to system/video card ram.
Some online games will store their visual elements into one huge file...good and bad. I believe games that do the 1 huge file thing is good for internet relay, but makes your system work at processing that data more.
It's like working textures via "old maid" or rolodex (huge contiguous data file is like rolodex). I prefer my system to work like old maid...they have enough memory and processing power to know where and what textures are needed, rather than having to flip through that rolodex to get what it needs. Sure the system might know the image is on the last page, but why make the hard drive work just to turn the pages? feh