>>714981764
Tempting, but almost all my roms are compressed in .7z when I'm not playing them, and after a little testing it seems I can save more space keeping them as-is.
>game.iso = 3,235,552 KB
>.iso compressed in .7z --> 1,946,668 KB (39.8% savings)
>.iso converted to .chd --> 2,162,392 KB (33.2% savings)
>.chd compressed in .7z (highest compression setting, Ultra) --> 2,161,326 KB (<0.01% savings)
So .iso seems to compress better, but .chd is better if you want access to all your games at once without having to decompress each time you play something new, which is understandable.