View Full Version : Slowdowns with bluetooth-connected controller

09.01.2018, 20:28
Have anybody experienced FPS slowdowns or lags when connecting controller over Bluetooth? I tried to google about the issue, but haven't found anything useful. What else can I do to find out the cause?

System details as per Cemu Support Rules: Windows 10, Ryzen 7, GTX 1060 (latest drivers as of today), Cemu 1.11.3 installed on HDD (more than 1TB free), 32 GB RAM, DualShock 4, Asus 400-BT dongle.

Here's what happens:

Whenever I connect the controller over Bluetooth, the FPS displayed in Cemu window title is about halved (seems to be actually halved an not just "dropping as far as...") and restored again only when the controller is disconnected again. There is a noticeable in-game stuttering. Even the computer itself feels less responsive at first, a USB-connected mouse gets laggy too, although that seems to recover after a minute or so (in-game FPS still stays low though). I haven't observed such issues with the controller without Cemu running, although it could be that the issue is amplified by the fact that Cemu is an emulator while normally the issue could be present, but not noticeable. There isn't any distinct difference in CPU usage between connected and disconnected controller states.

I thought maybe DS4Windows is to blame, but even with it disabled (exited completely), the slowdown still occurs immediately when controller is switched on.

The issue doesn't reproduce with the controller's USB connection, so I think it must be related to Bluetooth, perhaps drivers related, but I don't have enough knowledge to debug it further. I guess anything could be wrong in range of DS4 device driver, Bluetooth dongle driver, Bluetooth stack (?), Xbox 360 drivers,.. Sadly I don't have a different controller or a Bluetooth dongle to compare.

So the additional question is, who else uses a setup with DualShock 4 and how well does it work?

10.01.2018, 11:08
It would be odd to be related, but you can open Task Manager and see if anything goes very high CPU or RAM usage right after you connect it.