File copy to external SSD slows after three minutes


NickJP

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Windows 11 Pro
I have a Samsung SATA SSD (870 QVO 8TB) in an Orico 2139C3 drive enclosure (USB 3.1 Gen 1) connected to a USB 3.2 port on my desktop PC. When I initiate a large file copy from an internal SSD to the external drive, the copy runs at ~460MB/s for about the first three minutes, then abruptly slows to around 150-160MB/s for the remainder of the copy, for however long that takes. This behaviour is quite reproducible every time I perform such a copy.

Any ideas on why the copy always slows at this point, which corresponds to about 80GB having been copied.
 
Windows Build/Version
Win 11 Pro build 22000.593

My Computer

System One

  • OS
    Windows 11 Pro
    Computer type
    PC/Desktop
    Manufacturer/Model
    Gigabyte
    CPU
    Intel i5-12600K
    Motherboard
    Z690 Aorus Pro
    Memory
    128Gb
    Graphics Card(s)
    nVidia Quadro P1000
    Sound Card
    N/A
    Monitor(s) Displays
    BenQ PD3205U, Eizo EV3237
    Screen Resolution
    3840x2160, 3840x2160
    Hard Drives
    Samsung SSD 980 Pro
    Samsung SSD 970 EVO Plus
    Sabrent Rocket Q
    Case
    Be Quiet
Possible thermal throttling on either SSD with such a large continuous file.
 

My Computer

System One

  • OS
    Windows 10
Cache being full at this point?
 

My Computer

System One

  • OS
    Windows 11 RP
    Computer type
    PC/Desktop
    Manufacturer/Model
    Lenovo ThinkCentre M75Q-1
    CPU
    AMD Ryzen 5 Pro 3400GE @3.30 GHz (4.0 GHz Turbo)
    Motherboard
    Lenovo 3151
    Memory
    20 GB DDR4 2666 (1x16GB + 1x4GB)
    Graphics Card(s)
    AMD Radeon Vega 11
    Sound Card
    Integrated
    Monitor(s) Displays
    AOC 2369
    Screen Resolution
    1920 x 1080
    Hard Drives
    WD 512 GB NVME + SPCC 240GB SATA SSD
    PSU
    External 65W
    Case
    Mini (1L)
I have noticed the same thing when copying large files to drives in my external dock. It's also 3.1 plugged into a 3.2 port. I even blamed the speed fluctuation on the dock and got another one. I found the answer someplace that said when the write buffer gets full the speed slows down. The jargon was over my head so I just accepted it and let it be.
 

My Computers

System One System Two

  • OS
    Windows 11 Pro 23H2 22631.3007
    Computer type
    PC/Desktop
    Manufacturer/Model
    Dell Optiplex 7080
    CPU
    i9-10900 10 core 20 threads
    Motherboard
    DELL 0J37VM
    Memory
    32 gb
    Graphics Card(s)
    none-Intel UHD Graphics 630
    Sound Card
    Integrated Realtek
    Monitor(s) Displays
    Benq 27
    Screen Resolution
    2560x1440
    Hard Drives
    1tb Solidigm m.2 +256gb ssd+512 gb usb m.2 sata
    PSU
    500w
    Case
    MT
    Cooling
    Dell Premium
    Keyboard
    Logitech wired
    Mouse
    Logitech wireless
    Internet Speed
    so slow I'm too embarrassed to tell
    Browser
    Firefox
    Antivirus
    Defender+MWB Premium
  • Operating System
    Windows 10 Pro 22H2 19045.3930
    Computer type
    PC/Desktop
    Manufacturer/Model
    Dell Optiplex 9020
    CPU
    i7-4770
    Memory
    24 gb
    Monitor(s) Displays
    Benq 27
    Screen Resolution
    2560x1440
    Hard Drives
    256 gb Toshiba BG4 M.2 NVE SSB and 1 tb hdd
    PSU
    500w
    Case
    MT
    Cooling
    Dell factory
    Mouse
    Logitech wireless
    Keyboard
    Logitech wired
    Internet Speed
    still not telling
    Browser
    Firefox
    Antivirus
    Defender+MWB Premium
You may need to manually initiate a TRIM operation since an external drive is often not left attached for very long and may simply need an optimization.

Try this:

In File Explorer, right-click the drive letter of the external SSD and select Properties. Go to the Tools tab and click Optimize. Select the external drive and click Optimize.

NOTE: The optimization may appear to finish very quickly, but this is the time where Windows provides "hints" to the SSD telling it what blocks should be trimmed. I would let it sit after that for a few minutes, then test again to see if it consistently performs better now.

EDIT: If that helps, let me know and I'll describe in detail in the morning what this is doing.
 

My Computers

System One System Two

  • OS
    Win11 Pro 23H2
    Computer type
    PC/Desktop
    Manufacturer/Model
    Home Built
    CPU
    Intel i7-11700K
    Motherboard
    ASUS Prime Z590-A
    Memory
    128GB Crucial Ballistix 3200MHz DRAM
    Graphics Card(s)
    No GPU - CPU graphics only (for now)
    Sound Card
    Realtek (on motherboard)
    Monitor(s) Displays
    HP Envy 32
    Screen Resolution
    2560 x 1440
    Hard Drives
    1 x 1TB NVMe Gen 4 x 4 SSD
    1 x 2TB NVMe Gen 3 x 4 SSD
    2 x 512GB 2.5" SSDs
    2 x 8TB HD
    PSU
    Corsair HX850i
    Case
    Corsair iCue 5000X RGB
    Cooling
    Noctua NH-D15 chromax.black cooler + 10 case fans
    Keyboard
    CODE backlit mechanical keyboard
    Mouse
    Logitech MX Master 3
    Internet Speed
    1Gb Up / 1 Gb Down
    Browser
    Edge
    Antivirus
    Windows Defender
    Other Info
    Additional options installed:
    WiFi 6E PCIe adapter
    ASUS ThunderboltEX 4 PCIe adapter
  • Operating System
    Win11 Pro 23H2
    Computer type
    Laptop
    Manufacturer/Model
    Lenovo ThinkBook 13x Gen 2
    CPU
    Intel i7-1255U
    Memory
    16 GB
    Graphics card(s)
    Intel Iris Xe Graphics
    Sound Card
    Realtek® ALC3306-CG codec
    Monitor(s) Displays
    13.3-inch IPS Display
    Screen Resolution
    WQXGA (2560 x 1600)
    Hard Drives
    2 TB 4 x 4 NVMe SSD
    PSU
    USB-C / Thunderbolt 4 Power / Charging
    Mouse
    Buttonless Glass Precision Touchpad
    Keyboard
    Backlit, spill resistant keyboard
    Internet Speed
    1Gb Up / 1Gb Down
    Browser
    Edge
    Antivirus
    Windows Defender
    Other Info
    WiFi 6e / Bluetooth 5.1 / Facial Recognition / Fingerprint Sensor / ToF (Time of Flight) Human Presence Sensor
Try using FastCopy to copy large amounts of data. I know there is a bit of a learning curve, the documentation tends to be slightly confusing in a few ways, but it pays off nicely. IMO especially if you know how to use the command line options, it does.
Example 1 - Diff mode with Verify and a filelist:
Code:
C:\tools\FastCopy\FastCopy.exe /logfile=C:\tools\FastCopy\ErrorLog.log /filelog=C:\tools\FastCopy\FileLog.log /cmd=diff /force_start /verify=TRUE /balloon=FALSE /no_ui /srcfile=C:\tools\FastCopy\filelists\files.txt /to="<DestDir>"
Example 2 - Diff mode with Verify and specify the source directly instead of using a filelist:
Code:
C:\tools\FastCopy\FastCopy.exe /logfile=C:\tools\FastCopy\ErrorLog.log /filelog=C:\tools\FastCopy\FileLog.log /cmd=diff /force_start /verify=TRUE /balloon=FALSE /no_ui <file1> <file2> <...> /to="<DestDir>"

To keep an eye on the temperature of the drive, use HWiNFO (portable version) with the option to show icons on the System Tray for Drive Temperature and Drive Temperature 2 (from the S.M.A.R.T. category) and edit the settings to adjust the polling interval of the S.M.A.R.T. data captures.

Here is a copy of my HWiNFO64.INI file:
Code:
[Settings]
SensorsOnly=1
AutoUpdateBetaDisable=1
DarkMode=1
OpenSystemSummary=0
OpenSensors=1
MinimalizeMainWnd=1
MinimalizeSensors=1
MinimalizeSensorsClose=1
ShowWelcomeAndProgress=0
Autorun=1
SmartScanRate=20
Lang=en

You can make HWiNFO run automatically at startup. To get rid of the UAC prompt, add a task in Task Scheduler to make it run as an administrator (Run with highest privileges checkbox on the General tab of the task's Properties window) on every user logon (Triggers tab).

If you still want to be able to run HWiNFO like normal (i.e. without it automatically skipping to Sensors Only mode) you can keep a 2nd copy of HWiNFO Portable in a separate folder without putting the HWiNFO64.INI file in it (or still copy the file and edit the contents of the copied file) and create a separate shortcut if that's what you prefer.
 

My Computer

System One

  • OS
    11 Home
    Computer type
    Laptop
    Manufacturer/Model
    Medion S15450
    CPU
    i5 1135G7
    Memory
    16GB DDR4
    Graphics Card(s)
    Intel Iris Xe
    Sound Card
    Eastern Electric MiniMax DAC Supreme; Emotiva UMC-200; Astell & Kern AK240
    Monitor(s) Displays
    Sony Bravia XR-55X90J
    Screen Resolution
    3840×2160
    Hard Drives
    2TB SSD internal
    37TB external
    PSU
    Li-ion
    Keyboard
    Logitech K800
    Mouse
    Logitech G402
    Internet Speed
    20Mbit/s up, 250Mbit/s down
    Browser
    FF
Windows Defender and UAC scan files see disabling both will help.
 

My Computer

System One

  • OS
    Windows 11
    Computer type
    PC/Desktop
    Manufacturer/Model
    HP Pavilion
    CPU
    AMD Ryzen 7 5700G
    Motherboard
    Erica6
    Memory
    Micron Technology DDR4-3200 16GB
    Graphics Card(s)
    NVIDIA GeForce RTX 3060
    Sound Card
    Realtek ALC671
    Monitor(s) Displays
    Samsung SyncMaster U28E590
    Screen Resolution
    3840 x 2160
    Hard Drives
    SAMSUNG MZVLQ1T0HALB-000H1
The way an SSDs fast cache works can result in a huge performance drop when being fed large amounts of data, the reason being that when the cache is full the data needs writing out to the slower cells (this effect is much worse on QVL devices), if the amount of data going in is equal or exceeds the speed of writing then you will encounter a situation where everything has to slow down to allow data to be written out from the cache.
Normally the SSD waits for a lull in activity to write out the cache contents.
 

My Computer

System One

  • OS
    Windows 11 Pro 22H2, build: 22621.521
    Computer type
    PC/Desktop
    Manufacturer/Model
    Scan 3XS Custom 1700
    CPU
    Intel i7-12700K 3.6GHz Base (5.0GHz Turbo)
    Motherboard
    Asus ProArt Creator B660 D4
    Memory
    64GB DDR 3600Mhz
    Graphics Card(s)
    Asus Tuff RTX 3080 10GB OC
    Sound Card
    Onboard Realtek
    Monitor(s) Displays
    Gigabyte G32QC 32inch 16:9 curved @2560 x 1440p 165Hz Freesync Premium Pro/ Dell SE2422H 24inch 16:9 1920 x 1080p 75Hz Freesync
    Screen Resolution
    2560 x 1440p & 1920 x 1080p
    Hard Drives
    WD SN570 1TB NVME (Boot), Samsung 870QVO 1TB (SSD), SanDisk 3D Ultra 500Gb (SSD) x2, Seagate 3Tb Expansion Desk (Ext HDD), 2x Toshiba 1Tb P300 (Ext HDD)
    PSU
    Corsair RM1000X Modular
    Case
    Corsair 4000D Airflow Desktop
    Cooling
    Corsair Hydro H150i RGB Pro XT 360mm Liquid Cooler, 3 x 120mm fans, 1x Exhaust
    Keyboard
    Microsoft Ergonomic
    Mouse
    Logitech G402
    Internet Speed
    800Mbs
    Browser
    Edge Chromium
    Antivirus
    Defender, Malwarebytes
I have a Samsung SATA SSD (870 QVO 8TB) in an Orico 2139C3 drive enclosure (USB 3.1 Gen 1) connected to a USB 3.2 port on my desktop PC. When I initiate a large file copy from an internal SSD to the external drive, the copy runs at ~460MB/s for about the first three minutes, then abruptly slows to around 150-160MB/s for the remainder of the copy, for however long that takes. This behaviour is quite reproducible every time I perform such a copy.

Any ideas on why the copy always slows at this point, which corresponds to about 80GB having been copied.
This happens for everybody. It is just the crappy way windows handles file copies, coupled with ssd caches
 

My Computer

System One

  • OS
    Windows 10 Pro + others in VHDs
    Computer type
    Laptop
    Manufacturer/Model
    ASUS Vivobook 14
    CPU
    I7
    Motherboard
    Yep, Laptop has one.
    Memory
    16 GB
    Graphics Card(s)
    Integrated Intel Iris XE
    Sound Card
    Realtek built in
    Monitor(s) Displays
    N/A
    Screen Resolution
    1920x1080
    Hard Drives
    1 TB Optane NVME SSD, 1 TB NVME SSD
    PSU
    Yep, got one
    Case
    Yep, got one
    Cooling
    Stella Artois
    Keyboard
    Built in
    Mouse
    Bluetooth , wired
    Internet Speed
    72 Mb/s :-(
    Browser
    Edge mostly
    Antivirus
    Defender
    Other Info
    TPM 2.0
If frequently transferring large files or folders with a lot of files it may help to adjust Virtual Memory to give Windows more room to work in. I always did Win95/98/98SE and WinNT 3.51/4/2000, later versions had more RAM and was not as big an issue. Of course, planning large copies to run at other times to not interfere with production helps.
 

My Computers

System One System Two

  • OS
    Win11 Pro RTM
    Computer type
    Laptop
    Manufacturer/Model
    Dell Vostro 3400
    CPU
    Intel Core i5 11th Gen. 2.40GHz
    Memory
    12GB
    Hard Drives
    256GB SSD NVMe
  • Operating System
    Windows 11 Pro RTM x64
    Computer type
    PC/Desktop
    Manufacturer/Model
    Dell Vostro 5890
    CPU
    Intel Core i5 10th Gen. 2.90GHz
    Memory
    16GB
    Graphics card(s)
    Onboard, no VGA, using a DisplayPort-to-VGA adapter
    Monitor(s) Displays
    24" Dell
    Hard Drives
    512GB SSD NVMe, 2TB WDC HDD
    Browser
    Firefox, Edge
    Antivirus
    Windows Defender/Microsoft Security
Samsung QVO uses 4-bit cells, it´s a relatively low-cost, low-performance SSD. So the observed behavoir it to be expected, just live with it.
 

My Computer

System One

  • OS
    Windows 10

My Computers

System One System Two

  • OS
    Windows 11 22631.2861
    Computer type
    PC/Desktop
    Manufacturer/Model
    homebuilt
    CPU
    Amd Threadripper 7970X
    Motherboard
    Gigabyte TRX50 Aero D
    Memory
    128GB (4 X 32) Kingston DDR5 5200 (RDIMM)
    Graphics Card(s)
    Gigabyte RTX 4090 OC
    Sound Card
    none (USB to speakers), Realtek
    Monitor(s) Displays
    Philips 27E1N8900 OLED
    Screen Resolution
    3840 X 2160 @ 60Hz
    Hard Drives
    Crucial T700 2TB M.2 NVME SSD
    WD 4TB Blue SATA SSD
    Seagate 18TB IronWolf Pro
    PSU
    eVGA SuperNOVA 1600 GT
    Case
    Lian Li 011 Dynamic Evo XL
    Cooling
    Alphacool Eisbaer Pro Aurora 360, with 3 Phanteks T30 fans
    Keyboard
    Logitech K120 (wired)
    Mouse
    Logitech M500s (wired)
    Internet Speed
    1200 Mbps
  • Operating System
    windows 11 22631.2861
    Computer type
    PC/Desktop
    Manufacturer/Model
    homebuilt
    CPU
    Intel I9-13900K
    Motherboard
    Asus RoG Strix Z690-E
    Memory
    64GB G.Skill DDR5-6000
    Graphics card(s)
    Gigabyte RTX 3090 ti
    Sound Card
    built in Realtek
    Monitor(s) Displays
    Asus PA329C
    Screen Resolution
    3840 X 2160 @60Hz
    Hard Drives
    WDC SN850 1TB
    8 TB Seagate Ironwolf
    4TB Seagate Ironwolf
    PSU
    eVGA SuperNOVA 1300 GT
    Case
    Lian Li 011 Dynamic Evo
    Cooling
    Corsair iCUE H150i ELITE CAPELLIX Liquid CPU Cooler
    Mouse
    Logitech M500s (wired)
    Keyboard
    Logitech K120 (wired)
At 80GB? What cache is that large?
A lot of slower SSDs use an amount of their cells in SLC mode as a cache to speed up overall performance, QLC drives do this and can have a cache size between 50 - 120 Gb, a percentage of total drive size.
 

My Computer

System One

  • OS
    Windows 11 Pro 22H2, build: 22621.521
    Computer type
    PC/Desktop
    Manufacturer/Model
    Scan 3XS Custom 1700
    CPU
    Intel i7-12700K 3.6GHz Base (5.0GHz Turbo)
    Motherboard
    Asus ProArt Creator B660 D4
    Memory
    64GB DDR 3600Mhz
    Graphics Card(s)
    Asus Tuff RTX 3080 10GB OC
    Sound Card
    Onboard Realtek
    Monitor(s) Displays
    Gigabyte G32QC 32inch 16:9 curved @2560 x 1440p 165Hz Freesync Premium Pro/ Dell SE2422H 24inch 16:9 1920 x 1080p 75Hz Freesync
    Screen Resolution
    2560 x 1440p & 1920 x 1080p
    Hard Drives
    WD SN570 1TB NVME (Boot), Samsung 870QVO 1TB (SSD), SanDisk 3D Ultra 500Gb (SSD) x2, Seagate 3Tb Expansion Desk (Ext HDD), 2x Toshiba 1Tb P300 (Ext HDD)
    PSU
    Corsair RM1000X Modular
    Case
    Corsair 4000D Airflow Desktop
    Cooling
    Corsair Hydro H150i RGB Pro XT 360mm Liquid Cooler, 3 x 120mm fans, 1x Exhaust
    Keyboard
    Microsoft Ergonomic
    Mouse
    Logitech G402
    Internet Speed
    800Mbs
    Browser
    Edge Chromium
    Antivirus
    Defender, Malwarebytes
A lot of slower SSDs use an amount of their cells in SLC mode as a cache to speed up overall performance, QLC drives do this and can have a cache size between 50 - 120 Gb, a percentage of total drive size.
Thanks. I had no idea.
 

My Computers

System One System Two

  • OS
    Windows 11 22631.2861
    Computer type
    PC/Desktop
    Manufacturer/Model
    homebuilt
    CPU
    Amd Threadripper 7970X
    Motherboard
    Gigabyte TRX50 Aero D
    Memory
    128GB (4 X 32) Kingston DDR5 5200 (RDIMM)
    Graphics Card(s)
    Gigabyte RTX 4090 OC
    Sound Card
    none (USB to speakers), Realtek
    Monitor(s) Displays
    Philips 27E1N8900 OLED
    Screen Resolution
    3840 X 2160 @ 60Hz
    Hard Drives
    Crucial T700 2TB M.2 NVME SSD
    WD 4TB Blue SATA SSD
    Seagate 18TB IronWolf Pro
    PSU
    eVGA SuperNOVA 1600 GT
    Case
    Lian Li 011 Dynamic Evo XL
    Cooling
    Alphacool Eisbaer Pro Aurora 360, with 3 Phanteks T30 fans
    Keyboard
    Logitech K120 (wired)
    Mouse
    Logitech M500s (wired)
    Internet Speed
    1200 Mbps
  • Operating System
    windows 11 22631.2861
    Computer type
    PC/Desktop
    Manufacturer/Model
    homebuilt
    CPU
    Intel I9-13900K
    Motherboard
    Asus RoG Strix Z690-E
    Memory
    64GB G.Skill DDR5-6000
    Graphics card(s)
    Gigabyte RTX 3090 ti
    Sound Card
    built in Realtek
    Monitor(s) Displays
    Asus PA329C
    Screen Resolution
    3840 X 2160 @60Hz
    Hard Drives
    WDC SN850 1TB
    8 TB Seagate Ironwolf
    4TB Seagate Ironwolf
    PSU
    eVGA SuperNOVA 1300 GT
    Case
    Lian Li 011 Dynamic Evo
    Cooling
    Corsair iCUE H150i ELITE CAPELLIX Liquid CPU Cooler
    Mouse
    Logitech M500s (wired)
    Keyboard
    Logitech K120 (wired)
A lot of slower SSDs use an amount of their cells in SLC mode as a cache to speed up overall performance, QLC drives do this and can have a cache size between 50 - 120 Gb, a percentage of total drive size.
Thanks, that's the explanation. I found a review of the very drive I'm writing to on Toms Hardware, and they tested this. See Samsung 870 QVO SATA SSD Review: Taking Baby Steps With QLC (Updated) - look for a para titled "Sustained Write Performance and Cache Recovery", where they have a series of graphs showing what happens to the write performance with sustained writes for 15 minutes.
 

My Computer

System One

  • OS
    Windows 11 Pro
    Computer type
    PC/Desktop
    Manufacturer/Model
    Gigabyte
    CPU
    Intel i5-12600K
    Motherboard
    Z690 Aorus Pro
    Memory
    128Gb
    Graphics Card(s)
    nVidia Quadro P1000
    Sound Card
    N/A
    Monitor(s) Displays
    BenQ PD3205U, Eizo EV3237
    Screen Resolution
    3840x2160, 3840x2160
    Hard Drives
    Samsung SSD 980 Pro
    Samsung SSD 970 EVO Plus
    Sabrent Rocket Q
    Case
    Be Quiet

My Computer

System One

  • OS
    Windows 11 RP
    Computer type
    PC/Desktop
    Manufacturer/Model
    Lenovo ThinkCentre M75Q-1
    CPU
    AMD Ryzen 5 Pro 3400GE @3.30 GHz (4.0 GHz Turbo)
    Motherboard
    Lenovo 3151
    Memory
    20 GB DDR4 2666 (1x16GB + 1x4GB)
    Graphics Card(s)
    AMD Radeon Vega 11
    Sound Card
    Integrated
    Monitor(s) Displays
    AOC 2369
    Screen Resolution
    1920 x 1080
    Hard Drives
    WD 512 GB NVME + SPCC 240GB SATA SSD
    PSU
    External 65W
    Case
    Mini (1L)
With FastCopy, you should be able to see ~6.5% sustained write speed improvement until that 84GB cache is full and ~11% sustained write speed improvement until it no longer is full, i.e., when compared to the speeds that you have mentioned (and depending on factors).
 

My Computer

System One

  • OS
    11 Home
    Computer type
    Laptop
    Manufacturer/Model
    Medion S15450
    CPU
    i5 1135G7
    Memory
    16GB DDR4
    Graphics Card(s)
    Intel Iris Xe
    Sound Card
    Eastern Electric MiniMax DAC Supreme; Emotiva UMC-200; Astell & Kern AK240
    Monitor(s) Displays
    Sony Bravia XR-55X90J
    Screen Resolution
    3840×2160
    Hard Drives
    2TB SSD internal
    37TB external
    PSU
    Li-ion
    Keyboard
    Logitech K800
    Mouse
    Logitech G402
    Internet Speed
    20Mbit/s up, 250Mbit/s down
    Browser
    FF

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