For the last 3 years I have bought every version of the Dell XPS.
I started with the XPS 9360, XPS 9560, XPS 9570 and now just bought the XPS 7950.
I have also bought a lot of docks trying to get the best results for games even though I primarily use my laptop for work.
Razer Core, Razor Core X, Razer Core x Chroma, Dell TB15, Dell TB16 docks the and Akito Node Pro.
The reason I bought so many docks is because of getting poor DPC Latency issues. For the XPS 9560 the issue was because of Dell only using 2 PCI lines limiting the thunderbolt bandwidth to 20gbps.
Each new generation of Thunderbolt controllers or docks I figured would fix the issue. I found out the DPC Latency issue is there even if I didn't connect any docks.
So after the last 3 years of having this issue, this is how I managed to fix it:
1. Connect your eGPU.
2. Go to device manager.
3. Disable Display adaptors > Intel UHD Graphics 630.
For some reason Intel Graphics is causing micro stutters in windows when dragging windows around. Possibly due to it still sending packets of information to the external display or not being able to handle HDR10+ color at 4k (no idea). If I use just the Intel UHD 630 and the internal GTX 1650 there is no issue.
This fixes the issue though.
I'm really not sure why Intel UHD 630 is still being used when I have an external eGPU as the primary card and also an internal GTX 1650.
4. Disable Sound, video and game controllers > Intel Display Audio and Realtek Audio.
No need for Intel audio or Realtek if already using Nvidia's. For some reason MaxxAudio Pro is also pulling the sound data back from nvidias audio to add base effects. MaxxAudio base causes really bad base sounds for external speakers that already have a built in base. Not sure why its included, possibly because there were complaints of the internal speakers on the XPS 9570.
5. Uninstall Dell data vault.
This is using bandwidth for what I dont know. Maybe for encyrpting stuff on external HD's.
6. If using a LAN cable connection to you razer core go to Network adaptors and edit your network adaptor settings.
7. Disable ARP Offload
8. Set AutoDetach to EEPRROM
9. Energy efficient Ethernet Disabled.
10. Flow Control Disabled
11. Interrupt Modulation Rate to Low
We dont want the network adaptor to be to aggressive and eat up all the bandwidth.
12. Go to settings > Apps and Features
13. Uninstall all Realtek audio software and let windows install the default driver.
14. Uninstall MaxxAudio Pro.
This uses heeps of TB3 bandwidth to add additional base to sound.
I also removed dells supportassist and dells update software but I will leave that up to you to. I think its optional.
I can now play games like Doom and GTA 5 while getting around 90 - 130 FPS with my Nvidia RTX 2080 TI.
On my Dell Latitude 5400 (2019 model), I solved my problem of random audio / video freezes by disable "Dell Data Vault Control Device" in the system peripherals category of the device manager.
The fault to dddriver64Dcsa.sys which generate significant latencies visible with LatencyMon (called "Dell Diags Universal Device Driver" in this application).
I had initially contacted the Dell telephone service who didn't offer me this solution (when this problem was obviously already present in 2015 ! ), They must do "extensive research" and come back to me, I am still waiting ...
Hope you find it useful !