From what I'm reading, usually happens most on the front panel USB ports in regards to external storage devices causing an issue.

I have heard reports of weird behaviour with SMI controllers on NVME using PCH on X570 chipset too, might be related to the transfer speed issue you're having.

SX8200 Pro is quite popular in Malaysia and uses SMI, although that SSD is not worth buying anymore due to multiple stealth downgrades without any meaningful reduction in cost putting it in line with other SSDs using the same parts.

Possible reason yes. I am using a SX8200 Pro 1TB as the OS drive. It doesn't always happen, but when it does it is frustratingly slow. From 130+MB/s average, it would drop down to below 40MB/s average.

What's weird was that once I disabled torrenting (qbtorrent) the transfer speeds never dropped. But what's REALLY weird is that torrenting usually only uses very little bandwidth as the transfer speeds are below 10MB/s. But when I use say jdownloader2 for direct downloads, of which would max out my internet speed (over 50MB/s), transfer speed on the disk DO NOT drop.

Hmm.......just a query, do you use disk encryption on SX8200 boot drive? Bitlocker or Veracrypt?

EDIT: Have you try to turn on and off the disk caching? Cause every time after windows feature update, the disk caching functionality somehow "broken". Only turning it off and on again fixed it/

For the encryption part, if veracrypt is used.....lot of slow down......

This post has been edited by JohnLai: Feb 22 2021, 06:00 PM

Possible hardware, yes. Also more possibly is Windows problem. I give up on finding the root cause, instead as long as there's workaround I'll use it..
Example is I transfer files from PC to NAS can't maximized the bandwidth, play around with some settings and able to transfer full speed. Windows do some update then broken again.
Mount my PC drive in NAS and use NAS to do the transfer, every time can get full speed.

Now is trying to solve usb wifi intermittent disconnect on my HTPC, last time already solve it but same story, Windows update some things and it broke again.

USB Wifi, must be that darned Power Plan again.
USB Selective Suspend or that Wireless Adapter Setting Power Saving Mode.

It’s more of an AMD power management issue which is probably related to the USB issue... there’s a bigger picture rather than just a USB issue actually. Because it is also related to the PCIE, Ram and SATA, been giving me alot of headache when i was on ryzen. Never had such problem after moving to intel.

Now im interested to see how many more issues will appear since this has started to get noticed and people will most likely probe into this matter.

This post has been edited by Bonchi: Feb 22 2021, 09:01 PM

That one is the first thing I disable when use usb wifi or bluetooth. Power saving mode always create problems.

Except that my HTPC is using Intel CPU

wasnt talking about your problem but to john's USB wifi and power management problem about USB suspend settings with ryzen... it's a common workaround to Ryzen's USB dropping off.

Jangan shyok sendiri.

This post has been edited by Bonchi: Feb 23 2021, 12:33 AM

He's talking about my usb wifi problem.

And his problem is with AMD not intel. And Im giving him an insight because I have had that problem on 3 AMD rigs. But FYI, not on my new intel rig.

Huh? What you talking about? He don't have problem with his wifi. Beside his wifi is built in with motherboard.

The issue I described doesn't happen when using the main NVME slot that goes directly to CPU bypassing the chipset - is that the slot you're using?

Since everyone is talking about various issues with USB/NVME/wireless etc - some B550 boards also have LAN issues when using 2.5GBe Intel chips - apparently everyone blames Intel for it though, since the issue is more prevalent on Z490.

This post has been edited by yimingwuzere: Feb 23 2021, 10:29 AM

He specifically mentions about usb wifi and suspend settings. Are you even on the same page or your AMD fanboism got triggered until you cant read anymore.

Plus even if it’s “built in” to the mobo, how do you think it is connected, via magic? Man speaking of built in wifi, it reminds me of another nightmare i had with MSI B450 layout... but to be fair, this one is more on MSI fault.

This post has been edited by Bonchi: Feb 23 2021, 12:54 PM

Yes I'm using bitlocker. I'm aware of veracrypt causing slow downs, but that's a problem with the software itself since it also happens for Intel systems.


I don't remember exactly which chipset driver update did help alleviate the issue though, but there was one which helped transfer speeds to stay above 100MB/s most of the time. But like I said, there are still the odd times where it can just drop below 40MB/s for no reason.

Either ways as long as connection don't drop when file transferring, I cukur.


Yes I'm using the slot that is connected directly to the CPU lanes, not going through the chipset.

The i225V intel wifi/LAN controller is mostly fixed now I hear. Believe any latest revisions on B550 shouldn't have the bandwidth bug anymore.

Bitlocker? Which mode of encryption?

SSD built-in hardware encryption,
Bitlocker software (CPU AES-NI accelerated) 'Used Disk Space Only' or 'Fully Encrypted'?

There are reports on TRIM/Garbage Collection not working unless being triggered several times on bitlocker "Fully encrypted" mode especially then the SSD is OS drive.

As the result, users got normal turbo read speed while got slow 1GB/s for write speed.

Hardware encryption.

Understand that the transfer speed drop is NOT on the NVME. It's from an internal drive (SATA) to an external (USB 3.0).

Internal SATA to external USB3.0......

Hmmm......
Any info the the external USB3.0 drive?
Enclosure type (SATA/M2SATA/NVME) or WD/Seagate/Transcend type?
Is there UASP listed at Device Manager?

It's just a ugreen docker, so basically it's a SATA to USB converter as far as the connection is concerned. UASP is listed under device manager.

Then,I ran out of troubleshooting on your transfer speed slow down between internal NVME and external USB3.0

Lastly, any 2.4Ghz based wifi/bluetooth/mouse active? Ages ago, when 2.4ghz was common, it borked the USB3.0 transfer speed between 2 drives whenever Bluetooth or Wifi 2.4ghz are in use.

Other than that, no idea what really goes wrong.