On the PS4, true high compression is a myth perpetuated by malware distributors. Unlike PC, the PS4's security architecture (even when jailbroken) does not support real-time decompression of tiny archives into playable ISOs.
It is possible to see significant reductions, for instance, reducing a 60GB game down to roughly 20-30GB, saving considerable space on jailbroken consoles. 3. Usage Requirements ps4 iso games highly compressed repack