Drives in Thunderbolt enclosure very slow

@JDS99  Thunderbolt Control Center is the right place to be looking.  Device Manager doesn't show much for Thunderbolt, in fact on some early systems there was no indication of a Thunderbolt controller in Device Manager at all unless an actual Thunderbolt peripheral was connected, because otherwise the controller was completely powered off.

Just as a test to isolate variables, what happens if you connect the ThunderBay 4 directly to the system's Thunderbolt 3 port, i.e. without the dock being involved?  And do you have the older ThunderBay 4 that only has Thunderbolt 2, in which case I'm wondering if the Thunderbolt 3 to Thunderbolt 2 adapter you're presumably using could be a culprit, or do you have the newer Thunderbolt 3 version of the ThunderBay 4?

@JDS99  if the enclosure is called "Thunderbay", it seems a pretty safe assumption that it's a Thunderbolt enclosure.  The product page on OWC's website certainly suggests as much, and Thunderbolt chipsets that are backward compatible with regular USB-C systems only recently arrived, so if it is in fact a Thunderbolt enclosure, it wouldn't work over regular USB-C at all.  But the surefire way to tell would be Thunderbolt Control Center.  That ONLY lists Thunderbolt peripherals, not regular USB-C peripherals, so if you see your enclosure listed there, then it's operating over Thunderbolt.

15 MB/s is USB 2.0 speeds, so that's absolutely terrible.  Even a single spinning SATA HDD can manage 100 MB/s or so when it's not bottlenecked by something else (like USB 2.0), and the PCIe 3.0 x4 connection available from the XPS 13 9380's TB3 port definitely would not be a bottleneck on a SATA 6 Gbps HDD, a SATA SSD, or even multiple HDDs/SSDs.  For reference, PCIe 3.0 x4 is the same interface that the internal NVMe SSD uses, and that interface can handle 3 GB/s or more in real-world throughput.

All that said, file copies are also not great as a benchmarking tool because there are so many other factors there.  For example, copying 1000 files that are 1MB each will always take a LOT longer than copying a single file that is 1000 MB.  I'd use something like CrystalDiskMark to benchmark your disk to eliminate some of those variables and have a consistent test condition.

If you still see such poor performance even after cutting the dock out, there are still a lot of possible variables here, including the system, the Thunderbolt cable, the enclosure, and the actual disks in the enclosure.  Do you have some way to start isolating those variables, e.g. another Thunderbolt-capable system, another Thunderbolt cable, other disks you can install into the Thunderbay enclosure, and/or the ability to test the currently installed disks outside of the Thunderbay enclosure, such as through a SATA to USB adapter?  If the disks are set up as a RAID virtual disk in that enclosure, that last test would be tricky to do, though.

@jphughanThanks for your quick response.  I am testing that as I type.  The speed is similar - if anything, slower.  On the order of 15 MB/s with average response time around 450 ms (according to Task Manager).  Interestingly, the copy starts substantially faster, maybe 90 MB/s or so, but within 20 seconds it slows down.  I am copying a folder of 4 GB or so from the internal SSD to a new HDD in the enclosure, directly from one of the Thuderbolt ports, not through the dock. 

Interestingly, the enclosure itself does not say it is TB3, although there is a sticker on it that says so. 

I wonder if there is any way to tell if the ports are what they are supposed to be -- TB3, and if they are working properly. 

Thanks again! 

@jphughanI have tried some attempts to isolate the problem, but not systematically.  I have used more than one cable, through both TB ports on the XPS.  I have also used an e-sata enclosure with an e-sata to usb 3 connector into the usb 3 port, which did work faster than the TB3 enclosure.  That was a different, but older, drive.  I will try your suggestions.  Also, I need to get a hold of another TB enclosure somehow, essentially to determine if it is Dell or OWC that is the problem (the cables are all from OWC). 

Doing some online research, I saw that within this community someone was complaining about his TB performance.  It was fixed when Dell replaced his ports.  He was told that the ports can be damaged relatively easily and lose the TB performance.  Oh, I just found it again and saw that you had responded to him! 

So, if I can determine it is a port, I will ask Dell to look at them. 

Thanks again!

Based on @jphughan 's suggestion, I got CrystalMarkDisk to test the drives in the enclosure.  For the HDD, I got about read speed of 200 MB/s (8 queues 1 thread if that means anything to anybody) and write speed of 190 MB/s (same configuration).  That still seems much slower than what I should expect with TB3. 

I am going to follow up with Dell support. 

I bought an Samsung X5 external drive, which is an NVMe SSD using TB3.  Advertised as (up to) 2.8GB/s read and (up to 2.1GB/s) write speed.  I tested it using Crystal Disk Mark, and the read speed could have been in a Samsung ad.  However, the write speed is slower. 

Write speeds using the default setting on Crystal Disk Mark (all TB3) :

HDD in SATA enclosure: 200 MB/s

C Drive (NVMe): 2.7 GB/s

X5 (NVMe): 597 MB/s. 

So, it is 3 times faster than the HDD.  But I have to wonder why the write speed is so much slower than the C drive.  I would think this setup is among the fastest things available. 

Does anyone have any experience with these kinds of external drives that would suggest this is a reasonable write speed or not?  I'm still trying to determine if I should send the XPS back to Dell for a check on the ports. 

Thanks! 

could you please tell us where you enabled write caching?

Would you elaborate where and how did you enable writing cache?  I connected Razer Core X + 5700 XT to my Dell XPS 13 7390, 6 cores, 16GB, I played CS:GO but FPS is around 50 when watching another player but native 5700 XT performance should be around 300FPS+. I tried all drivers stuff but none of them worked.  So I wonder if the thunderbolt bandwidth is somehow limited.

@GodOfKamisama  the write cache option applies only to actual storage devices attached via USB, and it's a setting changed on the hard drive device in Device Manager.  An eGPU obviously is not a storage device and would communicate with the host system over PCIe, so that setting would not be available for your eGPU, nor would it affect available Thunderbolt bandwidth in any way.

In terms of your issue, you might want to create a new topic for better visibility given that this is totally unrelated to the original thread here, but if you're using an eGPU to accelerate content on the built-in display rather than having external displays connected to the eGPU's own outputs, then that would definitely introduce a performance hit because the system has to send data to the eGPU for rendering and then receive it back over Thunderbolt to display it on its built-in display.  If you can at least temporarily attach an external display to your eGPU, I suspect you'll notice an improvement there.  Beyond that, while it's true the XPS 13 can be had with 6 cores now, the fact remains that it's still a 15W U Series CPU that is optimized for low power, not something like a 45W H Series CPU optimized for high performance, as found in the XPS 15.  So it's possible that your CPU is bottlenecking your GPU.  In addition to that, the XPS 13's cooling system may not be adequate to support running the CPU maxed out all the time, in which case case the CPU would have to perform some thermal throttling that would further decrease performance and potentially further bottleneck the GPU.  Even the XPS 15 throttles under sustained heavy load, fyi.

Hi I am having exact same issue with my thunder bolt 3 drive conected to a Area 51m getting 200mbs

Please explain how to turn on write cache... I have looked but cannot find any where to enable it

Thanks

Rob

@sasman1964 @real_telemarker   Yes, you have to really want it! 

Go to the Properties settings for the drive (right click on the File Explorer drive icon, for example).  Then go to the Hardware tab.  Click the Properties button.  On the second Properties window on the General tab, click the Change Settings button.  You will need Admin privileges/password.  Go to the Policies tab, in the Removal Policy box.  Click the Better Performance radio button.  Then you can check the Enable write-cache box. 

Note that this could damage the volume if your enclosure is disconnected somehow while the system is writing to the drive.  And the USB-C connectors (Thunderbolt 3) are famous for being a bit loose. 

This will help a spinning HD with a SATA interface.  I believe it will help an SSD more, especially if it is on an NVM.e interface. 

Good luck! 

Hi,

Thank you so much !

I have a ticket open since weeks but DELL support (as usual) just ask to reinstall the drivers....

On my old macbook pro (2017) the transfert of a folder with thunsand RAW files takes less than 2 minutes ( 1,4 Gb/sec )  on the XPS it takes more than 15 minutes ( Same folder, Same Drive )

Thanks to your trick now my XPS climbs to 900 Mb / sec and take around 2:30