A compression ratio from ~6GB down to 500MB is extreme. While some "repacks" are legitimate, most 500MB versions achieve this through aggressive measures:
So next time you download a 100GB game without blinking, remember: somewhere, in a dusty forum archive, a 500MB ghost of Carbon is still seeding. And it’s winning. nfs carbon highly compressed 500mb
The Impossible File: How NFS Carbon Defied Physics at 500MB A compression ratio from ~6GB down to 500MB is extreme