@mmw2753 Mate I really feel your pain. With your fairly powerful PC (Desktop right?) you should expect very good PCVR result using a decent usb3 Link cable, esp. since you say the meta-link device/usb speed test results in showing at least 2.4Gbps. I use the official link cable connected to my z790mb usb3.2 gen2 type-c port and get 2.4Gbps with the speed test.
Unless you still have a Q3 hardware issue I suspect there may be something wrong with your overall meta/win11/nvidia setup/settings. I'll try to give you some suggestions on all these, based on what works very well for me right now. I have a bit more powerful desktop PC (i913900k/rtx4090) so I'll try to modify some of these for you but, in general, you should be able to use pretty well the same.
First of all, make sure you are not enrolled into the Quest PTC (pubilc test channel = beta) on either your Q3 or meta-link pc app (likewise for SteamVR btw). The current PTC v74 is a bit of a dog's breakfast right now. Just make sure you're on the latest v72 on both and you should be good to go. You may want to consider doing a Q3 factory reset and also download the meta-link pc app from the meta support website and run a Repair. Both those things can fix a lot of issues imho.
With meta-link PC app set device graphics settings to 80Hz refresh rate with the res slider full right. Also, go to the settings/general tab and select Oculus as your default OpenXR runtime. Lastly, disconnect any unnecessary usb devices so you don't run out of usb bandwidth. I don't see any differences between 80 and 90Hz refresh rates but if you do, try 90Hz with the res slider backed off 2-3 notches to the left of full right (~1.3x). Just avoid 120Hz refresh rates to start off with imho.
With Oculus Debug Tool, try enabling/using 900mbps Max Dynamic bitrate. This is quite different than what we normally use so you'll need to set things differently on ODT as well. I've found that using/enabling dynamic encoding bitrates since v72 works very well. This will then automatically set a bitrate based on your PC capability. With my PC I've found that this normally ends up using 700-750mbps encoding bitrate. Here's the ODT file I use;
I use the same ODT settings with Air Link and usually see 200-230mbps bitrate btw.
You'll often find that ASW modes will reset to defaults when you restart everything. I use the Oculus Tray Tool (OTT) game profiles to set this (and super sampling) but you can also do this manually with keyboard commands. Unless you have a full understanding of how OTT works you ay be better off avoiding using it right now.
In the case of ASW mode you can do these on the fly and this is very easy to do. If your keyboard has a numeric keypad (most modern keyboards have this located on the right side of your main keyboard) then you don’t even need to edit the ODT value (leave it at whatever it already is, usually Auto) and you can then use keyboard commands to change between ASW modes any time you like, including while actually running the app in VR. You can do this as many times as you like so you can monitor which seems to work best for you. With Link and Air Link (BTW but this doesn’t work with Virtual Desktop because it doesn't have the official Oculus runtimes, just their version of it) these are the keyboard commands;
Ctrl+num1 (numeric keyboard 1, not top row 1) = asw disabled
Ctrl+num2 = forced 45fps, asw disabled (actually ½ your refresh rate. So in my case, 80Hz = forced 40fps)
Ctrl+num3 = forced 45fps, asw enabled (again actually ½ your refresh rate)
Ctrl+num4 = asw auto (= default)
You can try these out on the fly to see what works best for you.
I suggest you try using the nvidia 560.94 driver because I think this is the most stable one out there right now. I use DDU using in safe mode to properly uninstall previous drivers beforehand (google how to do this). For Nvidia Control Panel global 3D settings I suggest you start off with everything at defaults except Power = prefer max performance, and below that setting Texture Quality change the Quality default to High Performance (this buys a few exrta fps without any loss in clarity).
Win11 graphics settings set hardware acceleration graphics (HAGS) = Disabled (this is enabled by default with win11 btw), and turn Game Mode = OFF.
All I can suggest right now mate. Give ALL of these a go (not just some of them) and see how you go. Feel free to report back and/or ask any questions. Good luck mate and cheers.
Edit; Also make sure you are not overclocking your cpu/gpu ot have any silly 3rd party so-called optimization apps. Some virus/malware checkers can cause problems so try to stick with the stock windows defender (and maybe do a scan or two). You may also want to check your win11 system file by running the windows system file checker (sfc/ scannow). google how to this.
