In September 2004, Sony unveiled its third major hardware revision of the PS2 (model number SCPH-700xx), also known as the slimline model. Available in late October 2004, it is smaller, thinner, and quieter than the original (fat) models and includes a built-in Ethernet port (in some markets it also has an integrated modem). The hardware was also given some minor changes, such as the Emotion Engine (EE) being clocked at a slightly higher CPU speed. Due to its thinner profile, the 3.5" expansion bay was completely removed and therefore does not support an internal hard disk drive. This results in incompatibility with games that require the HDD expansion, most notably Final Fantasy XI. An add-on to add HDD support to SCPH-7500x up to SCPH-9000x models called the HDPro was created but had limited success. It also has an external power supply as opposed to an internal one used in previous revisions, similar to the GameCube. A differently-shaped Multitap accessory was also released at the same time as the new revision due to design differences between the old and new PS2 models.
There were two sub-versions of the SCPH-700xx, one with the old separate Emotion Engine (EE) and Graphics Synthesizer (GS) chips and the other with the newer, integrated and unified EE+GS chip, but are otherwise identical. In early 2005, it was found that some slimline power transformers manufactured between August and December 2004 were defective and could overheat. These units were recalled by Sony and were replaced by a 2005 (and later 2006 and 2007) model.
The SCPH-700xx was succeeded by the SCPH-7500x in late 2005, which contained different ASICs than previous revisions. Like the SCPH-700xx, it also contained two sub-versions that had either separate EE and GS chips or the unified EE+GS chip. Some chips contained a copyright date of 2005 as opposed to 2000 or 2001 for earlier models. It also uses a different laser lens and has some compatibility issues with a different number of PS1 games and even some PS2 games. Later hardware revisions had better compatibility with PS1 games (Metal Gear Solid: VR Missions operates on most silver models); however, the later Japanese slim models had more issues with playing PS1 games than the first PS2 revisions.
On September 15, 2006, Sony released new hardware revisions of the PS2 (model number SCPH-7700x, with sub-versions as SCPH-7700xa and SCPH-7700xb). Initially released in Japan in both Black and Silver editions, it later saw release in North America, Europe and other parts of the world. This new revision exclusively uses the integrated, unified EE+GS chip as found in some SCPH-700xx and SCPH-7500x models, and has a redesigned ASIC, a different laser lens, and an updated BIOS and drivers.
On July 19, 2007, Sony started shipping another revision of the PS2 (SCPH-7900x) featuring a reduced weight of 600 grams compared to 900 g of the SCPH-7700x, achieved through a reduction in parts. This revision uses a smaller motherboard where the EE, RDRAM, SPU2 sound processor and IOP I/O processor were merged into a single ASIC while the GS was once again made as a separate chip, albeit in a much smaller form factor than previous PS2 revisions. The AC adaptor's weight was also reduced from 350 grams (12 oz) to 250 grams (8.8 oz).
Another refinement of the PS2 (SCPH-9000x) was released in Japan on November 22, 2007. As well as featuring some cosmetic changes, the design of the hardware was overhauled, incorporating the power supply into the console itself like the original (fat) PS2 models; this increased the overall weight of the console to 720 grams (25 oz). On SCPH-9000x series consoles manufactured after the third quarter of 2008 as the last revision of the PS2 (indicated by date code 8C), some changes were made to incorporate a revised BIOS that patches an exploit found in all other models that allowed homebrew applications and software to be launched from a memory card.
The slimline model of the PS2 was initially released in black, however a silver edition was made available in Japan, United Kingdom, Germany, Australia, United Arab Emirates and other GCC countries, France, Italy, South Africa, and North America. A limited edition pink console was also made available after March 2007.