PCSX2 new update brings PS2 emulation improvements for more responsive gameplay

PCSX2 Reliquary’s new update focuses on something that can be surprisingly noticeable in emulation: audio latency. That’s the small delay between what happens on screen and when you actually hear it. In most games, a few extra milliseconds won’t ruin the experience. But in rhythm games, fighters and anything built around tight timing, it can make controls and sound feel slightly disconnected. The new Reliquary update tackles that problem directly. It adds a low-latency audio synchronisation mode, changes how the emulator handles small audio buffers and introduces two extra Windows audio options. The goal is simple. Get sound out faster without causing a mess when emulation speed changes.

A new way to keep audio in sync

The biggest change is the new low-latency sync mode. Normally, PCSX2 can use time stretching to keep audio sounding correct when emulation speed moves around. That works well, but it also adds processing and buffering. More buffering means more delay.

Reliquary now takes a different approach during normal gameplay. It uses resampling and small speed corrections to keep audio lined up, with adjustments limited to around plus or minus 1 per cent of the target speed.

That lets the emulator work with much smaller buffers. When everything is running at full speed, the new method keeps the audio path short. If the game starts running slowly or the player uses fast-forward, Reliquary switches back to TimeStretch instead. That matters because aggressive resampling during larger speed changes can make audio sound rough. The emulator doesn’t try to force the low-latency mode into situations where it doesn’t fit.

TimeStretch was adding noticeable delay

TimeStretch isn’t bad technology. It solves a real problem. PCSX2 uses SoundTouch to adjust audio while keeping pitch reasonably stable when emulation speed changes. The catch is that SoundTouch needs a certain amount of audio ready before it can do its job. That adds latency.

Under the existing configuration, the processing itself can account for roughly 40 ms of extra delay. Even with other audio settings pushed down, testing still put total latency at around 80 ms in some configurations.

The new mode cuts out much of that extra processing while the game is running normally. In one Linux test using a low-latency PulseAudio setup, measured end-to-end audio latency dropped to around 11 ms with settings pushed to their minimum. That doesn’t mean everyone will suddenly get 11 ms. Audio hardware, drivers and operating-system settings all matter. Still, it shows what the new path is trying to achieve.

Reliquary pushes audio buffers lower

There’s another interesting change underneath the surface. Reliquary also changes how it deals with latency limits reported by cubeb, the audio library used by the emulator. An audio backend might report that a certain buffer size is the minimum it supports. Reliquary’s testing found that those numbers aren’t always a hard limit.

In one example, the Pulse backend reported a minimum latency of 25 ms. Requesting just 1 ms still produced a working buffer of roughly 120 frames, which came out to around 4 ms in that setup. So Reliquary now asks for lower values instead of automatically stopping at the reported minimum. If the hardware and driver can handle it, the emulator can get a smaller buffer. If they can’t, results will naturally vary.

Windows gets two new audio options

Windows users get some of the biggest practical changes. The update adds WASAPI Exclusive Mode, which gives the emulator direct access to the audio device. On suitable hardware, latency can fall below 3 ms. There is a catch.

Exclusive mode does exactly what the name suggests. PCSX2 takes control of the device, so other applications can’t use the same output at the same time. Windows system mixing is bypassed as well. The second new option is IAudioClient3.

It’s a newer Windows audio interface designed to support lower shared-mode latency. On WaveRT-compatible hardware, Reliquary reports that it can also reach figures around 3 ms or lower without requiring exclusive access.

That’s a more convenient setup for everyday use because other applications can keep playing audio. On systems without the required hardware support, IAudioClient3 can fall back to around 10 ms, which puts it closer to standard WASAPI shared mode.

This update is mostly about responsiveness

Reliquary has several experimental features in development, including soft-float recompilers, paraLLEl-GS work and support related to PlayStation 2-based arcade hardware. This release is much narrower.

It’s about getting audio from the emulator to your speakers or headphones with less waiting in between. There aren’t sweeping graphics changes here, and this isn’t framed as a huge compatibility update.

For players, the difference will depend heavily on their setup. Some systems will cope with tiny buffers easily. Others won’t. Windows audio hardware can vary a lot, and Linux configurations can behave differently depending on the sound stack in use.

Still, the direction of the update is clear. PCSX2 Reliquary is cutting unnecessary audio processing where it can, giving Windows users more backend choices and pushing buffer sizes lower when the hardware allows it. For games where timing matters, that’s the kind of change you can actually feel.

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