Question Transfer rate decrease with multiple drives?

bror31

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Oct 13, 2019
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Hello people, I hope you are keeping good!
I'm experiencing a huge transfer speed drop down on nearly every ssd,hdd that I have, and I'm wondering if anyone can give me a hint of what could be.

I'm uploading several screenshoots that shoows how it starts with a proper write speed and you will notice how it drops to 70ish MBPS after a while.

I tried in many different drives and the result is always the same.
to
First Screenshoots is transfering from a SSD Samsung 860 QVO to an external HDD WD. It started 180 MPB and you can see droped to 70.

Second screenshoot is transfering from a SSD WD BLUE to a Samsung860 QVO, again starts at 480ish MBP and drop to 70. (The SSD WD Blue is an external disk connected via USB C)

Third screenshoots shows a transfer from my internal SSD'd both are Samnsung 860. Again, from 480ish drops after a while to 70.

I did tried with more several dist and result is always the same.

My pc is an i9 9900k , 64 GB ram and rtx 2070.

Any help would be appreciated! Thanks!


SS n1:
https://drive.google.com/file/d/1V4o_iOUWYjVcZoM5i0dXLwJyeprwIbL4/view?usp=sharing

SS n2:
https://drive.google.com/file/d/1Uu1DwcQ2Up-bR_zJDFwpn6jXBJkKUak4/view?usp=sharing

SSn3:
https://drive.google.com/file/d/1DnlMml6cAPFyKIRmjA2Q5iS73lLKUcgK/view?usp=sharing
 

Ralston18

Titan
Moderator
Open Task Manager or Resource Monitor (use both but only one at a time) so you can monitor system performance.

Without doing anything just observe for awhile until the system is stable.

Leave the window open and start the transfer. Watch what the system does during the initial transfer process and then watch for what changes with/when the speed drops.

It make take some trial and error to "focus" on the specific components etc. to detect some specific change that correlates with the speed drop.

Maybe something launching in the background.....
 

USAFRet

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Mar 16, 2013
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Transferring to an HDD - Once the cache on the HDD fills up, it WILL go slower.
Transferring to the QVO - That particular drive is slow in sustained operations, like copying large data. Good for burst, not so good for sustained.
 

bror31

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Oct 13, 2019
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Transferring to an HDD - Once the cache on the HDD fills up, it WILL go slower.
Transferring to the QVO - That particular drive is slow in sustained operations, like copying large data. Good for burst, not so good for sustained.

Thanks very much for your reply!

Idk if would be the same issue, but even downloading from a SD card from the laptop SD reader, the same occurs. I have a 300MB /s SD card, which starts with that nice burst of 300 MB/s and again, afterr a while, the transferr speed goes down to 70MB.
Now the werid part of this scenario is that from the SD card I'm transfering to my NVMe M2 Samsung 970 EVO Plus, which is my main SSD, supossed to transfer 3500 MB/s.. so no QVO involved in this operatioin, yet results are the same.. I thought was worth mentioning it.
 

USAFRet

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Mar 16, 2013
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"from the SD card I'm transfering to my NVMe M2 Samsung 970 EVO Plus, which is my main SSD, supossed to transfer 3500 MB/s.. "

No.
Performance is dictated by the slowest device in the chain.
The SD card cannot deliver data at that 3500MB/s rate.
 

bror31

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Oct 13, 2019
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"from the SD card I'm transfering to my NVMe M2 Samsung 970 EVO Plus, which is my main SSD, supossed to transfer 3500 MB/s.. "

No.
Performance is dictated by the slowest device in the chain.
The SD card cannot deliver data at that 3500MB/s rate.
I know that. It delivers data at 300 MB/s (The SD card speed) , yet, after 1/2 minutes drops down to 70 MB/s aswell. If I transfer from my QVO to the M2 EVO 970 or frorm any source to the EVO 970, it will drrop down to 70 aswell. Not only in the QVO. My point was that even on a NVM disk, the transfer drops to 70 MB
 

bror31

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Oct 13, 2019
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Here I did a few more test and all of them arre very interersting... and frustrating.




Test 1: In this case I thought I should try my maiun NVME m2 Samsung EVO 970. Which has a max speed of 3500 MBs. I have this drive in my pc among with two QVO previously mentioned.

Here comes the catch again... when transfering from my QVO to the EVO 970 it also starts sweet constant rate of 550 mb, after 2 minutes, drops down to 70MB again.



Test 2: Just to make sure, I tried also from a WD BLUE SSD to my 970 EVO and the samme occurs. Now I know its impossible the write speed of a 970 EVO can be 70 MB... this just doesnt sounds okay. And I know its not the WD BLUE as I use that to record 4 K video, and I can record continuously at a rate of 240 MBs until I fill that disk... so it has to be something else.



Test 3: I transfered to my 970 EVO from my Sandisk extreme pro uhs-II (300 MB/s) a card I use to record also, 4K video and which I can record non stop until is finished... and again, we start with a nice transfer of 280 MB and afterr 1 or 2 minutes, back to 70 MB...



Test 4: here comes the most interesting part.. I have a second laptop from 2014, i5 8gb ram, and I upgraded it with a WD Blue SSD... when transferring into that laptop there is no transfer speed drop at all.... hence my reason to belive it has nothing to do with drives as I tried, HDD, SSD, NVME, and SD CARDS, all giving the exact same results and transfer drops go exactly to 70 MB/s....



Thanks again!
 

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