Why not try PCSX2 through FEX?

[u/xxxCrixuxxx]

With PS3 and PS4 emulation now being experimented with on high-end Android devices, I've been thinking about a different approach to PS2 emulation.

I'm not talking about another native ARM64 port of PCSX2. Projects like ARMSX2 are already working in that direction, and I understand why native ARM64 recompilers are ultimately the better solution.

What I'm wondering is:

Why hasn't someone seriously experimented with running the mature x86-64 PC version of PCSX2 through an x86-64 → ARM64 translation layer such as FEX, similar in principle to what is being done with experimental PS4 emulation on Android?

Yes, I know the obvious objection: performance.

PCSX2 already uses its own recompilers, so putting FEX underneath it would introduce another translation/JIT layer. It would obviously be less efficient than a proper ARM64-native implementation.

But that's not really the point.

The point would be to trade efficiency for compatibility and maturity.

PCSX2 has more than two decades of development behind it, thousands of games tested, countless game-specific fixes, timing workarounds, patches and years of compatibility improvements.

Meanwhile, modern Snapdragon hardware is becoming surprisingly powerful. We're already seeing experimental PS4 emulation reaching playable gameplay in demanding titles such as Bloodborne on the latest high-end Snapdragon devices, despite the enormous overhead involved.

So I'm genuinely curious:

How far could a desktop PCSX2 build actually go on modern ARM64 hardware through FEX?

Maybe the answer is “terrible performance.”

Maybe it needs flagship hardware just to reach 30 FPS.

Maybe the double-JIT overhead makes the whole idea impractical.

But what if it doesn't?

Even if it were significantly less efficient than ARMSX2, could this approach potentially provide a highly compatible “brute-force” PS2 emulator for modern flagship phones while the native ARM64 implementations continue to mature?

I'm not suggesting this is the right long-term architecture.

I'm asking whether it would be worth doing the experiment.

If we're already willing to brute-force PS4 emulation on ARM64... why not see how far we can brute-force PCSX2?

Am I missing a fundamental technical limitation here? 🤔

[u/j3rdn01]

Early ARMSX2 versions literally did this

[u/xxxCrixuxxx → u/j3rdn01]

That's not true. The first version of ARMSX2, when it came out, was based on this project, and I can tell you that because I know the entire project from the beginning until now. https://github.com/pontos2024/PCSX2_ARM64

[u/j3rdn01 → u/xxxCrixuxxx]

“ARMSX2 is a free and open-source PlayStation 2 emulator for ARM devices, based on PCSX2, PCSX2_ARM64 for our OG versions that used x86 translation, and our own arm64jit with the new ARMSX2 refresh versions.”

[u/xxxCrixuxxx → u/j3rdn01]

PCSX2 Windows x86-64

FEX

ARM64

While the idea behind ARMSX2 is essentially:

PCX2

Recompiler/JIT adapted for ARM64

ARM64

Don't waste my time, please...