sometimes ram is taken up by background programs. also fragmentation of the hard drives can make a difference. connection speed doesn't usually effect online games. i frequently play at LAN centers and all the computers have the same setup, the same programs installed, virtually no background programs, and all run of a broadband/lan hub and some computers load at slower rates.
probably fragmentation. also, for some reason the age of the machine really effects how fast things start.
i've got a 7 year old brick, and a lot of the progs i use on it are the same. 5-7 years ago, the thing would have started the programs in 3 seconds, now it frequently freezes and takes ridiculously long times to load. even though i do have more hard drive space, and less background progs.
temperature sometimes effects how they run.
the video card i should expect wouldn't effect loading time, because for most games, they are loading the same 3d parts, textures and info. that would only effect the refresh rate - how fast it works.
don't dwell on it.