Is there any difference between zipped and uncompressed roms?

[JeanLuc]

Is there any difference between zipped and uncompressed(like .smc or .n64) roms when playing them? Are the graphics different or clearer or anything?

[Muscab]

Nop. They're zipped so that the size will be smaller. Once you downloaded them, you can uncompress them and drag them out of the zip and their size will be back to the original. So nothing changed.

[Polizzi]

An exception would be the arcade roms though. Can't use them otherwise

[Zorlon]

A few rom may load slightly faster uncompressed (I'm talking micro seconds though so nothing noticable)

psp games compressed into cso (depending on the game and media card used on an actual PSP) may cause some slow downs during play (this will never apply to compressed roms though as they are fully loaded by the emulator

some cd based emulators that have support for compressed CD images (some ePSXe CD plugins can do this) may lag

To sum it up
roms (cart based games) will run perfectly from zipped compressed images (images are fully loaded so access during play does not happen and no slow downs will happen)
disc (CD/DVD or other disc formats) may lag during play as access to disc during play may be slowed (there are a number of factors here that can cause this)