V0 did not have a built-in DVD player and instead relied on an encrypted player that was copied to a memory card from an included CD-ROM (normally, the PS2 will only execute encrypted software from its memory card, but see PS2 Independence Exploit).
Two propositions were to name the old model (EE and GS, separate chips) V11.5 and the newer model V12, and to name the old model V12 and the newer model V13.
Later hardware revisions had better compatibility with PlayStation games (Metal Gear Solid: VR Missons works on most silver models).
Due to its thinner profile, it does not contain the 3.5" expansion bay, and therefore does not support the internal hard disk drive but due to the presence of USB 2.0 ports an external USB Hard disk can still be used, and now uses an external power supply, like the Gamecube.
These included a PCMCIA slot instead of the Expansion Bay (DEV9) port of newer models.
Only a few million users had obtained consoles by the end of 2000 due to manufacturing delays.
As of V4 everything was unified into one board, except the power supply.
Developers also complained that it was difficult to develop for the system, with little in the way of reference material from Sony for its exotic architecture.
However the New Slim Silver Models have more issues with playing PlayStation games than the first PS2 revisions.
In preparation for the launch of a new, slimmer PlayStation 2 model (SCPH-70000), Sony had stopped making the older PS2 model (SCPH-5000x) sometime during the summer of 2004 to let the distribution channel empty out stock of the units.
This allowed the PS2 to tap the large install base established by the PlayStation.
