I’ve had the Prime 4+ Since August 2025 from new, running the latest firmware, and just wanted to pipe in that I also have this issue. I’ve used it a lot since I bought it and I’ve tried to self diagnose it myself. The unit will be fine when you first boot it, but after maybe 2 or so hours it starts to slow down as time progresses and can get reeealy slow if you have it on for like 8 or so hours.
Initially I thought it was my storage, but I’ve replaced it with a very quick Crucial SSD that’s far in excess of what should really be needed to play music. I have around 12k songs on the SSD and it’s sitting below 200GB in storage used. The library has been exported straight from the latest version of Engine DJ Desktop. I’ve ran my library through mp3tag and removed any strange characters from the metadata and have downsized the artwork of all my songs to a very low size.
I also use TIDAL streaming on the unit alongside my local library. I’ve had nights where I’ve used exclusively Tidal and exclusively my local library and the issue seems to happen no matter where the music is coming from.
When it starts to slow down it becomes very difficult to actually use the unit, especially if you’re an open-format DJ like I am and constantly need to sort through playlists and search for songs. The waveforms start to lag, and sometimes if you trigger a loop it can just freeze the waveforms entirely for a few seconds. If you switch between Tidal and local storage it can take a long time to do anything.
I honestly do not believe that this is caused by the unit getting too hot. At one of my gigs, I play alongside a band. When the band are on, if I restart the unit it immediately goes back to normal and it takes another few hours for it to start slowing down again.
I love the unit (I own an RX3 too and the Prime4+ does blow it out of the water when it’s working properly. the RX3 is also tremendously buggy and just freezes sometimes) but I’ve also had issues with build quality (the paint is starting to come off the unit already…) and in general I don’t think I could trust the unit at a gig where I would need to play for a prolonged period of time.
The whole reason I bought the unit was because it is advertised as an all in one. I shouldn’t have to rely on a backup source of music to restart it to make it usable again. I suspect it’s poor memory/ram management. either that or there’s an issue with the CPU in these units but I doubt it. I think the latest firmware has improved the situation slightly but there’s still a problem somewhere.