SCPH 5x00y cut the weight of the console down again (to me, it feels like half the weight of the model 30000s) and the fan is even quieter. The i.Link port (4-pin firewire, instead of the standard 6-pin firewire) was removed starting with this series. An infrared sensor was built into the system between the Eject and Reset/Power buttons, eliminating the need for an IR adapter in a controller port, as old systems needed to use a remote. This series also marks the first time the PS2s were set to blacklist known unlicensed discs from booting, such as Action Replay/Game Shark (they were the same thing since GameShark came out in North America, until GameShark2 version 3, which is actually another European cheat device known as XPloder, and made by Blaze), Code Breaker, XPort/SharkPort, etc. Only unlicensed discs newer than that PS2 model would boot on such system.
I have a feeling Sony starting blacklisting cheat device software much earlier it might explain why my v3.3 action replay cdx "made in 1999" doesn't boot on my v7 ps2.

