XPS 8920, starting issue

By the way, I had just assumed you didn't do something like install Win7 on your XPS8920. You never responded to the question which version you're running

Win10 and 8 are the only two versions using UAS protocol. If you want to call the manufacturer of the disks, they're more than likely going to refer you to M$. I suggest starting at least with tier 2 support and escalate to tier 3 level. Windows support is message/chat 

How to see UAS is being used by Win 10 

Open Device Manager

• Expand the 'Storage Controllers' node 
• Look for USB Attached SCSI (UAS) Mass Storage Device
• If not there, expand the 'Universal Serial Bus controllers' node
• Double click 'USB Mass Storage Device'
• On the Driver tab click the Driver details 
• Look for UASPStor.sys  That means UAS Protocol 

One screenshot and pasted text on another post does show Win 10.  I missed that. sorry

You could try to see whether "USB Attached SCSI (UAS) Mass Storage Device" in Device Manager is showing a power management tab. It isn't likely that it does, but if it shows up there, you can try to 'enable' it. Enabling that allows you to set the computer to turn off USB devices to save power. Also in Device Manager, there won't likely be the option to allow you to manually update the UAS driver under "USB Mass Storage Device", or under "USB Attached SCSI (UAS) Mass Storage Device". But if 'Update Driver' is listed as an option, I would give that a try. 

Not only does your PC hardware, software, and firmware all have to support UAS, but if you're using one, a hub has to support it.. . cables too. I don't know if you're using a hub from years gone by, but if you are, check into that.   

@Steve2473 

Did you make any modifications before the reboots started ? Or were the reboots starting to happen right after installing the USB drives ? Did you add more internal storage ? 

Did you ever install Crystal disk Info and check the status of the NVMe drive?

CrystalDiskInfo - Crystal Dew World [en] (crystalmark.info)

After installing the Standard edition, click the Function tab > Advance Feature > Raw Values > 10[Dec]

See if it's showing a warning. Also check for seek, write or read errors

Not sure what you used for doing a memory test. I suggested Passmark MemTest 86

PassMark MemTest86 - Memory Diagnostic Tool - Technical Information

There's a user guide at the bottom the page

Any chance you have a spare PSU ?

What does Reliability History show? Any errors just before a reboot?

You checked device manager? Are any devices not loaded correctly?

Note:  I'm experiencing an issue that's preventing me signing-in to the Dell community. I may not be able to respond always 

attached, device manager all ok. where do i check reliability history,any errors just before reboot, in event viewer? memtest, i used the onboard diagnostics before booting windows, set on thourgh and it went for 6 hours

brand new direct from dell, the test is when i hit the f12 key for boot up options, the dell diagnostic

@Steve2473 

I know you said you didn't do anything since you purchased the system. Did you purchase the system new 'Out Of The Box' or from an original owner ? 

Check out the SK Hynix PC300 as well as the secondary HDD with Crystal Disk Info

The Passmark MemTest 86 is a better test than the built-in Windows Memory Diagnostics as far as thoroughness

To find RM, go to control panel > security and maintenance > click the maintenance drop down arrow >view reliability history

or just type in the search box next to Start "Reliability History"

It's only when the USB drives are connected/turned On when you have the restarts, or have you had it happen when all the USB drives are disconnected?

What are all the application error messages saying on the days that have the red X's ?

Did you have the USB drives connected/turned on when you opened Crystal Disk to look/check their status ?  

Do you know how to get to Disk Management?

Control Panel > Admin Tools > Computer Management. In the left pane under storage click Disk Management

With all the USB drives connected, are they all reading Online?

yes, crystal disk all drives online