Problem with oldest wifi clients?

Hello. I am using a 4a Gigabit Edition router, openwrt 22.03.5 installed. While I do not experience any speed problems on new generation wifi devices, I experience speed fluctuations on old type wifi devices. What could be the reason for this? Features such as SHORT GI are disabled (I also tried them on, the result did not change)

Wow.

  • How old are these devices?
  • What are they?

I don't think you can magically speed up an old device (e.g. a device that only does 802.11b).

I have a Samsung np550pc-s05tr(made in 2013) laptop, my laptop wifi card is Intel® Centrino® Advanced-N 6235 Dual Band and I am experiencing this problem with it. It connects to the router with 300mbps, the distance between me and the router is 1.5 meters and there is no wall in between. Also, I have no problems with my tplink ax1800 device, which I use for 4a gigabit edition stock rom and other tests. This speed fluctuation problem only occurs when openwrt is installed.