So found out the dpc latancy iusse is still happening with out being connected to a dock.

After Disabling sound drivers under software comonents.

I seem to haver fixed a lot of issues removing dells secure storage driver in device manager. i think it interfers with the thunderbolt connection. not had a crash for quite a while. need to remeber dells l.atops are normally for business so removing this sort of stuff for gaming is not going to be an issue.

aving researched and tried many things I have eventually made a small change and believe my system now works fine. I have a bottom of the range 2019 Dell G3 3590 with i7 9750H CPU and Cubase Pro.

Very briefly, LatencyMon showed ACPI.sys to be the main culprit of spikes occurring on CPU 0. There are lesser issues too and lots of advice out there about Bios settings, Windows configurations, power settings and how the DAW is used.

As far as I can see, the many tweaks make little difference so I've left things standard except:

1) I launch Cubase so it uses all CPUs (0 to 11) except 0 and 1 using the shortcut "C:\Windows\System32\cmd.exe /c start "" /affinity FFC "C:\Program Files\Steinberg\Cubase 10\Cubase10.exe". Note that /affinity is set to "FFC" (hex) as I want to use CPUs 2 to 11. This alone appears to have killed ACPI.sys spikes and results in steady low CPU usage. Affinity can be set for your specific CPU on the Details tab in Task Manager every time you load Cubase or automatically using software, however, this shortcut is free. You need to set Affinity (the "FFC" part) according to the number of (virtual) CPUs you have (see below).

2) For a little extra comfort, I sometimes disable the Wifi adapter. On my desktop I have a shortcut to Control Panel - Network Connections to make this easier.

3) For a little more comfort, in Cubase I have recorded tracks routed to one (or more) multi-channel VSTi (Halion Sonic SE) rack instruments, and my live keyboard track is routed to a separate rack instrument to reduce the CPU load on live playing. Secondly, I also use the Steinberg Audio Power Scheme under Studio Setup - VST Audio System. Thirdly, I still have the option to "freeze" the recorded tracks VSTi but with CPU use averaging 20% it seems unnecessary.

4) C-States, Hyper-threading and other Bios settings and all other tweaks I read about appear unnecessary. The main issue for me appears to be the occasional spikes on CPU0 and sometimes CPU1 so I force Cubase to use other CPUs.

To calculate affinity:

1) I worked it out in decimal (result was 4092) to use cores 2-6 (CPUs 2-11) using store.tomandmiu.com/cal-cam.php

2) I converted the decimal result of 4092 to hex (result was FFC) using www.rapidtables.com/convert/number/decimal-to-hex.html

My CPU now appears to run steadily at about 10% to 20% or less when playing several MIDI tracks and live keyboards with an ASIO setting of 256 (it will run fine with ASIO much lower too).

Hope you have some luck with this.

And this is why I haven't dropped $2000 for Dell. Why would I want to buy a two year old problem that they still can't fix?

Using DELL XPS 15 9560, still hopelessly bad latency with BIOS
1.14.3, this has not been resolved for the last 2 years.  Thanks for the embarrassing inoperative HDMI port on the BIOS release before this one.
ACPI.sys still the main issue.
There must be something drastically wrong with the architecture of the XPS for this not to be resolved, given there have been 2 model releases since the issue was known. Other vendors fix their issues in a timely manner.

The issue also appears in other computers. I have a Lenovo Legion Y530 and have been suffering from similar problem. I also experience audio clicks and pops when I repeatedly press the screen brightness controls on the keyboard (Fn + F5 or F6 keys on my Lenovo).

So since the bios update my dell tb15 dock has become unusable because of lag but my node pro has no issues.

I worked out how to unpulge the node properly. To hot unplug I just turn the monitor off first.

I installed the windows may creators update on my xps 15, it's a 3y old model. And I noticed a better latency in traktor pro whild dj-ing. Only got a spike in the beginning of 2000us after it settled to around 500us. Maybe worth giving a shot ... .

The new bios helped a little as some have stated but still occasional spikes. I feel Microsoft should be looking into this also.

I went for the pro version because it has 2 thunderbolt 3 ports. Just stick a USB hub in one and can have wired mouse and keyboard.

Ok i went out and bought a Akitio node pro. Everything works. no lag, full speed network, plays games in 4k.

very disapointed in razer. big waste of money.

1 thing i did not try was using the hdmi port instead of DP. That might have reduced the bandwidth some what.

ok problem is back. I have now noticed the USB ports on the razer are only showing 3 in device manager. also it does not matter which razor core usb port i plug my mouse and keyboard into they will not be working when i restart. i have to uplug and plug into a different razor core usb port.

Just plugged in a USB network card and transfered a 4k film. seems a better. Need to see what happens.

Just put the network speed to 10mbps again and everything is running fine.

If i change the network to 1gpbs again the network will disconnect every few seconds.

I can only conclude that the razer have put a cheap network and USB controller chipset.

still having major issues. every time i restart something different is not working.

I ran Latency Monitor:

Your system appears to be having trouble handling real-time audio and other tasks. You are likely to experience buffer underruns appearing as drop outs, clicks or pops. One or more DPC routines that belong to a driver running in your system appear to be executing for too long. Also one or more ISR routines that belong to a driver running in your system appear to be executing for too long. One problem may be related to power management, disable CPU throttling settings in Control Panel and BIOS setup. Check for BIOS updates.
LatencyMon has been analyzing your system for  0:00:16  (h:mm:ss) on all processors.