[SOLVED] Understanding Download Speeds and Read/Write Speeds

Jcharby

Honorable
Oct 17, 2015
47
1
10,535
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Hi all,

Hoping someone can share some understanding on how download speeds, internet speeds, and read/write speeds are correlated. I just installed a Samsung 970 EVO SSD and started a download via steam on it but noticed a few thigs in the task manager performance tab

  • Disk usage is very low during downloads at only ~2%
  • Read/Write speeds currently are looking like 100-400 KB/s / ~60 MB/s in task manager
  • Download speed in steam is 30 MB/s with peak of 34
  • Wifi download speed is ~ 250 MB/s (Not using ethernet, for some reason ethernet is significantly slower then wifi)
I suppose my questions are the following:
  • Why is the final download speed not reflective of disk write speed or the network download speed if (presumably) hardware is not the issue
  • Why is only 2% of the SSD being utilized for download?
  • Is this evidence of a bottleneck or issue occurring somewhere?
  • Is the issue on the end of the network/serverI am downloading from and not my system?
I was not expecting to get the advertised speeds of 3,500/2,500 MB/s, but I find it curious how small the final read/write speeds are compared to the other numbers and theoretical hardware capability.

If it is relevant, I am running an AMD 5600x on the MSI B550M Pro Wifi downloading to the aforementioned Samsung 970 EVO SSD

Thanks!
 

kanewolf

Titan
Moderator
Hi all,

Hoping someone can share some understanding on how download speeds, internet speeds, and read/write speeds are correlated. I just installed a Samsung 970 EVO SSD and started a download via steam on it but noticed a few thigs in the task manager performance tab

  • Disk usage is very low during downloads at only ~2%
  • Read/Write speeds currently are looking like 100-400 KB/s / ~60 MB/s in task manager
  • Download speed in steam is 30 MB/s with peak of 34
  • Wifi download speed is ~ 250 MB/s (Not using ethernet, for some reason ethernet is significantly slower then wifi)
I suppose my questions are the following:
  • Why is the final download speed not reflective of disk write speed or the network download speed if (presumably) hardware is not the issue
  • Why is only 2% of the SSD being utilized for download?
  • Is this evidence of a bottleneck or issue occurring somewhere?
  • Is the issue on the end of the network/serverI am downloading from and not my system?
I was not expecting to get the advertised speeds of 3,500/2,500 MB/s, but I find it curious how small the final read/write speeds are compared to the other numbers and theoretical hardware capability.

If it is relevant, I am running an AMD 5600x on the MSI B550M Pro Wifi downloading to the aforementioned Samsung 970 EVO SSD

Thanks!
You will be limited by the slowest link in the chain.
But first, some terminology clarifications -- Network speeds are megabits ( Mb/s ) and downloads are usually megabytes ( MB/s ). So your 250Mb will be 30MB.
Your disk usage WILL BE very low. A 970 EVO can benchmark at 3000+ MB/s. So 30MB/s will be 1% of that maximum performance.
 

kanewolf

Titan
Moderator
Hi all,

Hoping someone can share some understanding on how download speeds, internet speeds, and read/write speeds are correlated. I just installed a Samsung 970 EVO SSD and started a download via steam on it but noticed a few thigs in the task manager performance tab

  • Disk usage is very low during downloads at only ~2%
  • Read/Write speeds currently are looking like 100-400 KB/s / ~60 MB/s in task manager
  • Download speed in steam is 30 MB/s with peak of 34
  • Wifi download speed is ~ 250 MB/s (Not using ethernet, for some reason ethernet is significantly slower then wifi)
I suppose my questions are the following:
  • Why is the final download speed not reflective of disk write speed or the network download speed if (presumably) hardware is not the issue
  • Why is only 2% of the SSD being utilized for download?
  • Is this evidence of a bottleneck or issue occurring somewhere?
  • Is the issue on the end of the network/serverI am downloading from and not my system?
I was not expecting to get the advertised speeds of 3,500/2,500 MB/s, but I find it curious how small the final read/write speeds are compared to the other numbers and theoretical hardware capability.

If it is relevant, I am running an AMD 5600x on the MSI B550M Pro Wifi downloading to the aforementioned Samsung 970 EVO SSD

Thanks!
You will be limited by the slowest link in the chain.
But first, some terminology clarifications -- Network speeds are megabits ( Mb/s ) and downloads are usually megabytes ( MB/s ). So your 250Mb will be 30MB.
Your disk usage WILL BE very low. A 970 EVO can benchmark at 3000+ MB/s. So 30MB/s will be 1% of that maximum performance.
 

geofelt

Titan
How full is the target ssd?
The more full it is, the harder the device needs to work to find free nand blocks to write to.
Once a sequential write fills the 512MB of DDR4 ram cache, the data needs to be unloaded to the underlying nand chips.
On an empty drive, things go fast, like in benchmarks.
Once full, data gets moved around requiring a read/write process.
ssd space management can usually do all this cleanup in the background.

What is the temperature of the ssd?
If it is too high, it will throttle. Operating temperature is up to 70c.
HWmonitor can tell you what the current, min and max ssd temperatures are.
I do not know what the throttle point is.

Benchmarks operate in an overlapped manner where there is always data available to write to the ssd.
In a download situation, I think this may not be happening.
The app reads some data, writes it and waits for completion before reading the next data.
In windows device management, there is a setting to control ssd buffering.
It controls if you confirm a write is actually on the device before proceeding.
This can be bypassed if you are not concerned about lost data if an untimely power failure should happen.
 

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