Flood göndermek, insanların floodlarını okumak ve diğer insanlarla bağlantı kurmak için sosyal Floodlar ve Flood Yanıtları Motorumuza kaydolun.

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Flood göndermek, insanların floodlarını okumak ve diğer insanlarla bağlantı kurmak için sosyal Floodlar ve Flood Yanıtları Motorumuza giriş yapın.

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3 ve kadim dostu 1 olan sj'yi rakamla giriniz. ( 31 )

Üzgünüz, Flood yazma yetkiniz yok, Flood girmek için giriş yapmalısınız.

Lütfen bu Floodun neden bildirilmesi gerektiğini düşündüğünüzü kısaca açıklayın.

Lütfen bu cevabın neden bildirilmesi gerektiğini kısaca açıklayın.

Please briefly explain why you feel this user should be reported.

Can anyone explain this weird file copy behaviour? Copying from an NVME to a USB 3.1 drive.

Can anyone explain this weird file copy behaviour? Copying from an NVME to a USB 3.1 drive.

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33 Yorumları

  1. That’s just how it be somtimes. It’s nothing to worry about.

  2. 68 MB/s still is faster than what my PC is giving me

  3. Never call your flash drive speedy. It will disappoint you.

  4. Is your USB 3.1 drive an HDD?
    If so, it might have an SMR drive in it which slows significantly when the cache is full.

  5. Could also be overheating.

    m.2 drives tend to throttle when they get too hot and usually could use a heatsink.

    Click on the drive temp in HWINFO to pop a graph and then run the copy to see how the temp changes.

  6. Every file system is different, but usually you can read about ZFS’s Intent Log (ZIL) to get an idea of what is going on.

  7. That usually happened to me, when the drive was transferring small files.

    I’d suggest looking into Fast Copy.


    I set the cache / buffer setting to 8 gigs, on my rig that has 64 gigs, and the files transfer very smoothly.

    1. **FastCopy is the Fastest Copy/Backup Software on Windows**
    2. It supports UNICODE and over MAX_PATH (260 characters) file pathnames.
    3. Because it uses multi-threads for Read/Write/Verify, Overlapped I/O, Direct I/O, so it brings out the best speed of devices.
    4. It supports Include/Exclude filter like a UNIX wildcard.
    5. It runs fast and does not hog resources, because MFC is not used. (Designed using Win32 API and C Runtime only)

  8. If this were an engine, I’d say you are hitting the governor limit.

  9. I’ve also noticed that large files transfer faster than a bunch of small files. So a 5gb file will transfer faster than 500 10mb files.

  10. Several users are saying cache, which is probably true. I have also seen this behavior due to usb drives overheating, and gripping them to provide some cooling (through my body) improved the results. this was with a metal shelled usb drive which was very hot when writing.

  11. What’s the scale of this graph?
    It’s definitely because the cache is full, but I have a hunch that the scale of the graph is distorting how big of a difference there actually is

  12. Considering you have a pretty fast USB drive, it is basically an SSD.

    To cut costs down, basically any SSD you can buy today has MLC (multi aka 2), TLC (triple) or QLC aka quadruple level cells that drastically reduce cost, increase data density but are much slower to write to (and somewhat less reliable but that doesn’t really matter), so to reach high write speeds, the SSD has either an SLC cache to soak up a bunch of data before writing to the slower but cheaper cells or it writes to multiple level cells in single bit mode to increase speed, the issue with that is that the cache obviously has less capacity than the whole drive and thus gets filled up relatively quickly which will drop you down to the write speeds of the multi level cells. Nothing to worry about, just an artifact of modern solid state storage systems

  13. User: copy this 1GB file to a flash drive

    OS: (1 sec) done!

    User: unmount the drive

    OS: (nervous laugh) ok, give me a minute

  14. Cache filled up. Lots of solid state media uses write caching to compensate for slow write speed. Once the cache fills up, the speed drops considerably as the drive now has to write data from both the cache and wherever you are copying from.

  15. It’s the drives cache, once the cache fills up the speeds will slow down and bounce around just like you are seeing here. Happens on high performance SSDs as well, most of them have a caching mechanism.

  16. If your USB 3.1 is also a flash drive, and it’s been used before, it could also be hitting a wall with pages previously marked free but haven’t actually been freed yet. Basically garbage collection. Cache could also be the cause, a stated by many others, or a combination of both, plus just Windows being Windows.

  17. The sawtooth pattern is due to [exponential backoff](https://en.wikipedia.org/wiki/Exponential_backoff). The speed is progressively increased until a ceiling is met (i.e.: can’t go faster), then it backs off and increases speed again. It’s the fastest way of doing it.
    Depending on what your drive is HDD or SSD (can’t really tell by the graph, could be either) that is due to different sorts of caching (SLC cache for SSD or writing to the edge of the disk for a DM-SMR drive.

  18. Nowadays many SSD have cells that can be programmed to behave both like TLC and QLC.
    Usually you first write at high speed to the free TLC and when it’s filled you start writing to the QLC portion of the memory.

    After a while the SSD will be reprogrammed such that the filled TLC is converted in a slower type of memory and programming the free QLC portion of the SSD as TLC.

    It can also be other types of cells, not necessarily only T and QLC.

    Edit: it can also be cache but considering the amount of file you transferred at high speed it probably isn’t the case. Cache is usually about 1 or 2GB on high end SSD and Windows 10 only use cache in reading operation unless you change some settings. This is to prevent data losses while writing.

  19. Cache saturation/overflow. The drive can’t write the data as fast as it is receiving it, so it caches it. Eventually the buffer fills up and you get this bounce behavior as it flushes/fills/flushes/fills.

  20. Maybe the USB drive has a write cache that is smaller than the amount of data you transferred? What USB drive are you using?

  21. The write cache on the USB drive looks be filling up requiring the device to finish writing the data before clearing the cache and accepting new data which explains the large burst of speed in the beginning and then the sudden drop and sawtooth pattern

    This is a common thing to see on some/most USB storage drives that I have seen

  22. Perhaps the drive’s cache is full. Writes usually go directly to the (fast) cache before being written to the actual flash memory.