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Question I am getting only 130 MB/s write speed on my SSD

May 18, 2020
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Hey guys,

So my new SSD (Samsung EVO 860 500GB) arrived today and I cloned my windows to it. I tested the read/write speeds by moving a 60 GB file from HDD to SSD and the speed I am getting is only 100-130 MB/s. I tried running the Crystal Disk Mark benchmark and it says the read/write speeds are around 500 MB/ps which sounds about right. The SSD is connected to SATA 3 port.

Is this kinda difference normal when it comes to moving/copying files manually?





Thank you
 

USAFRet

Titan
Moderator
Mar 16, 2013
125,987
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Hey guys,

So my new SSD (Samsung EVO 860 500GB) arrived today and I cloned my windows to it. I tested the read/write speeds by moving a 60 GB file from HDD to SSD and the speed I am getting is only 100-130 MB/s. I tried running the Crystal Disk Mark benchmark and it says the read/write speeds are around 500 MB/ps which sounds about right. The SSD is connected to SATA 3 port.

Is this kinda difference normal when it comes to moving/copying files manually?

Thank you
Speed is dependent on the slowest device in the chain. Here, the HDD.
The SSD can only read what the HDD can deliver.

Garden hose (HDD) and fire hose (SDD). No matter the capacity and potential flow rate of the fire hose, if you're feeding it with a garden hose...that is all you will get.
 
Reactions: Makaveli
May 18, 2020
12
1
15
0
well because the hdd is slow, so the write speed is only around that max write/copy of hdd.
Speed is dependent on the slowest device in the chain. Here, the HDD.
The SSD can only read what the HDD can deliver.

Garden hose (HDD) and fire hose (SDD). No matter the capacity and potential flow rate of the fire hose, if you're feeding it with a garden hose...that is all you will get.
This makes sense but I am writing to SSD in this case and not reading. Will still the low HDD speed matter?

If yes, then I presume the best way to test it out is create another partition on SSD and then try moving the files, right?

Or am I just thinking too much about it and should be satisfied with the benchmarking test? ;)
 

USAFRet

Titan
Moderator
Mar 16, 2013
125,987
4,393
159,940
19,749
This makes sense but I am writing to SSD in this case and not reading. Will still the low HDD speed matter?

If yes, then I presume the best way to test it out is create another partition on SSD and then try moving the files, right?

Or am I just thinking too much about it and should be satisfied with the benchmarking test? ;)
Yes, the HDD still matters.
The SSD can only write as fast as the HDD can serve it up.
In either direction, the slowest device in the chain dictates performance.

If CrystalDiskMark is showing 500+MB/s, all is good.
 
Reactions: Makaveli
May 18, 2020
12
1
15
0
Yes, the HDD still matters.
The SSD can only write as fast as the HDD can serve it up.
In either direction, the slowest device in the chain dictates performance.

If CrystalDiskMark is showing 500+MB/s, all is good.
Bruh your HDD has read speed limitations which are -probably suspiciously around the figures you're observing-.

Not sure why you would expect a higher data rate when you have to read data from that device before you can write it to another device..
Understood. Thank you guys :)
 
Reactions: beers
Hey guys,

So my new SSD (Samsung EVO 860 500GB) arrived today and I cloned my windows to it. I tested the read/write speeds by moving a 60 GB file from HDD to SSD and the speed I am getting is only 100-130 MB/s. I tried running the Crystal Disk Mark benchmark and it says the read/write speeds are around 500 MB/ps which sounds about right. The SSD is connected to SATA 3 port.

Is this kinda difference normal when it comes to moving/copying files manually?





Thank you
Lots of single small files take a lot more time. Also make sure you are running on a unique SATA channel. Running on the same channel (multipliers) means the data has to be sent over the same bus twice.

There's also the possibility you are out of SLC cache. In that case 100->130MB/s is good. I've seen them go down to 20MB/s under heavy load and no SLC cache left.

Also check the smart report for CRC errors. You might have a bad cable.

EDIT: Saw you are copying from HDD. Your HDD is the bottle neck.
 
Last edited:
May 18, 2020
12
1
15
0
Lots of single small files take a lot more time. Also make sure you are running on a unique SATA channel. Running on the same channel (multipliers) means the data has to be sent over the same bus twice.

There's also the possibility you are out of SLC cache. In that case 100->130MB/s is good. I've seen them go down to 20MB/s under heavy load and no SLC cache left.

Also check the smart report for CRC errors. You might have a bad cable.

EDIT: Saw you are copying from HDD. You're HDD is the bottle neck.
@digitalgriffin, I have four SATA ports on my mobo. So unless I am not using any cable splitter, it'd mean I am running on a unique channel, right? Also, the cable is new.
 

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