The best you can do is play the official PSP Stories games, which are excellent games in their own right.
There is for the PSP. Rockstar Games never released a port for this handheld console.
The Myth of the GTA San Andreas PSP ROM: Truth, Compression, and Best Alternatives gta san andreas psp rom highly compressed best
Searching for a "highly compressed" GTA San Andreas ROM for the PSP is a common pursuit, but it is important to clarify that an official version of Grand Theft Auto: San Andreas was never released for the PlayStation Portable (PSP)
They assembled a ragged crew—TJ, a demolition-minded ex-con; Mei, a coder who could ghost security cameras; and Padre, an old friend with church connections and an uncanny way with people. Plans collapsed and reformed: a staged traffic jam, a roof-side ambush, a make-shift EMP, and a chase across the salt flats that left cars smoking and loyalties tested. The best you can do is play the
Be cautious of links claiming to have the "full game" for the PPSSPP emulator. Since the game was never built for PSP architecture, these files are frequently clickbait or contain unrelated software. Review of Fan-Made Port Projects
Because an official PSP version of San Andreas does not exist, any website claiming to offer a "100% working official GTA San Andreas PSP ROM" is misleading you. Technical Barriers: Why a Port Was Impossible The Myth of the GTA San Andreas PSP
Because these are unofficial ports, they are prone to frequent crashes, especially on the PSP 1000 model due to its lower RAM (32MB vs. 64MB in later models).
Set anisotropic filtering to Off or 2x to keep the retro feel while saving processing power. Safety Warning
Before you search for a "gta san andreas psp rom highly compressed best", it's essential to understand the safety and legal risks.
The PSP received three official GTA titles: GTA: Liberty City Stories , GTA: Vice City Stories , and GTA: Chinatown Wars . Because San Andreas was too large and complex for the standard PSP hardware, the actual game cannot run natively on the console.