NvME SSD write speed

[Morrie Sells Wigs]

So, I have a new SSD and while downloading a game from Steam I was fiddling about, looking at stuff...blah blah blah...and I went into Task Manager and looked at the C drive (my SSD) and noticed that the write speed is fluctuating, from as low as 8 or 9 MB/S to 30ish MB/S.

 

I Googled it and it seems this number is very low, meaning slow, so I'm a little confused.

 

I don't have blistering internet speeds, but that shouldn't matter (should it?) and the drive is not full (I think there's still 250+ GB left on it), so I'm concerned.

 

I did see a Reddit post that mentioned something to do with "disabling the windows write cache" and lots of people said it worked, so I'm tempted to try it but I don't actually know what it'll do and I'm hopeful someone can confirm or refute the quality of that advice and suggest something else if it's not the best option.

 

Please, if anyone can help, it'll be appreciated.

 

Thank you.

[Nuzicx]

The steam game could be installing in "components" or the download is heavily compressed, both resulting in low write speeds.

 

Please use a tool like CrystalDiskMark and post results

[Morrie Sells Wigs]

4 minutes ago, Nuzicx said:

The steam game install may not require such a high write speed or the file could be heavily compressed causing a low write speed.

 

Please use a tool like CrystalDiskMark and post results

Thank you, Nuzicx, I'll try that.

[podkall]

SSD model and total size?

[Eigenvektor]

43 minutes ago, Morrie Sells Wigs said:

I don't have blistering internet speeds, but that shouldn't matter (should it?)

Of course it does. Steam can't write data to disk faster than it is arriving over the internet.

 

For game updates: Game files are usually patched, rather than overwritten. That takes more time than a straightforward write operation. This allows downloads to be smaller/faster, by only downloading the difference between old files and new files, then updating the files accordingly.

 

~edit: If data is compressed as @Nuzicx said, the disk can't write data faster than it is arriving, multiplied by the compression factor. E.g. if download speed is 10 MB/s, and it decompresses to 4x that amount, then your maximum write speed would be limited to 40 MB/s. However, if your CPU isn't fast enough to decompress it at that speed, you could also be limited to some speed below that.

[Morrie Sells Wigs]

3 hours ago, podkall said:

SSD model and total size?

It's the WD SN850X 1tb.

[Morrie Sells Wigs]

3 hours ago, Eigenvektor said:

Of course it does. Steam can't write data to disk faster than it is arriving over the internet.

 

For game updates: Game files are usually patched, rather than overwritten. That takes more time than a straightforward write operation. This allows downloads to be smaller/faster, by only downloading the difference between old files and new files, then updating the files accordingly.

 

~edit: If data is compressed as @Nuzicx said, the disk can't write data faster than it is arriving, multiplied by the compression factor. E.g. if download speed is 10 MB/s, and it decompresses to 4x that amount, then your maximum write speed would be limited to 40 MB/s. However, if your CPU isn't fast enough to decompress it at that speed, you could also be limited to some speed below that.

I didn't think download speed was related to the write speed of the SSD, but that's my inexperience...hence the request for advice.

 

I get confused between MB/s and Mb/s.

 

Is Mb/s the same as Mbps?

 

According to internet speed test I get about 80-90 Mbps down and 25 up (10 ms Latency).

 

Does this equate to 8-9 MB/s?

[Morrie Sells Wigs]

3 hours ago, Eigenvektor said:

Of course it does. Steam can't write data to disk faster than it is arriving over the internet.

 

For game updates: Game files are usually patched, rather than overwritten. That takes more time than a straightforward write operation. This allows downloads to be smaller/faster, by only downloading the difference between old files and new files, then updating the files accordingly.

 

~edit: If data is compressed as @Nuzicx said, the disk can't write data faster than it is arriving, multiplied by the compression factor. E.g. if download speed is 10 MB/s, and it decompresses to 4x that amount, then your maximum write speed would be limited to 40 MB/s. However, if your CPU isn't fast enough to decompress it at that speed, you could also be limited to some speed below that.

 

My CPU is 8c12t (5200).

 

[Eigenvektor]

1 minute ago, Morrie Sells Wigs said:

I didn't think download speed was related to the write speed of the SSD, but that's my inexperience...hence the request for advice.

The maximum achievable write speed of your SSD is independent of your download speed. But the speed at which data is actually written to the disk during a download depends on the speed it arrives at.

 

Your SSD may be capable of 500 MB/s or more, but if you're downloading a game at 10 MB/s (80 Mbps), then there's nothing that would currently require/allow it to write at that speed. Compression adds variability on top of that, because some data may compress better than other data. So 10 MB/s might turn into 40 MB/s after decompression or only 20 MB/s or any other reasonable multiple.

 

Simply put, a Steam download is not a good way to benchmark your SSD, because there are a ton of factors that can influence at which speed the SSD is utilized.

 

--------

To avoid confusing, I would recommend to use Mbps rather than Mb/s to refer to download speeds. Easier to distinguish from MB/s. In any case MB/s is simply Mbps divided by 8. It's simply different units, like centimeter, meter and kilometer.

[Morrie Sells Wigs]

3 minutes ago, Eigenvektor said:

The maximum achievable write speed of your SSD is independent of your download speed. But the speed at which data is actually written to the disk during a download depends on the speed it arrives at.

 

Your SSD may be capable of 500 MB/s or more, but if you're downloading a game at 10 MB/s (80 Mbps), then there's nothing that would currently require/allow it to write at that speed. Compression adds variability on top of that, because some data may compress better than other data. So 10 MB/s might turn into 40 MB/s after decompression or only 20 MB/s or any other reasonable multiple.

 

Simply put, a Steam download is not a good way to benchmark your SSD, because there are a ton of factors that can influence at which speed the SSD is utilized.

 

--------

To avoid confusing, I would recommend to use Mbps rather than Mb/s to refer to download speeds. Easier to distinguish from MB/s. In any case MB/s is simply Mbps divided by 8. It's simply different units, like centimeter, meter and kilometer.

Ah, ok, I appreciate your advice and the clarification around the difference between MB and Mb.

[Eigenvektor]

29 minutes ago, Morrie Sells Wigs said:

According to internet speed test I get about 80-90 Mbps down and 25 up (10 ms Latency).

 

Does this equate to 8-9 MB/s?

1 Megabyte per second (MB/s) -> 8 Megabit per second (Mbps or Mb/s)

 

80 – 90 Mbps = 10 – 11.25 MB/s

25 Mbps = 3.125 MB/s

[podkall]

46 minutes ago, Morrie Sells Wigs said:

It's the WD SN850X 1tb.

very good drive, as @Eigenvektor explained, write speeds aren't the only thing that affect download, install or even updates

 

data compression saves drive space and bandwidth for the overall internet and servers,

 

there's also so many data the thing, which is probably CPU that uncompresses them, can hold

 

if you eat food, and your stomach is full, you can't just tell your stomach to digest faster, and you can't just shove more food into it either

[Morrie Sells Wigs]

50 minutes ago, Eigenvektor said:

1 Megabyte per second (MB/s) -> 8 Megabit per second (Mbps or Mb/s)

 

80 – 90 Mbps = 10 – 11.25 MB/s

25 Mbps = 3.125 MB/s

Thank you, for your patience.

 

I understand the difference now, cheers, mate.

[Morrie Sells Wigs]

40 minutes ago, podkall said:

very good drive, as @Eigenvektor explained, write speeds aren't the only thing that affect download, install or even updates

 

data compression saves drive space and bandwidth for the overall internet and servers,

 

there's also so many data the thing, which is probably CPU that uncompresses them, can hold

 

if you eat food, and your stomach is full, you can't just tell your stomach to digest faster, and you can't just shove more food into it either

I get what you mean...makes sense.

 

So, it's a decent drive and I shouldn't worry about it?

[podkall]

1 hour ago, Morrie Sells Wigs said:

I get what you mean...makes sense.

 

So, it's a decent drive and I shouldn't worry about it?

decent would be an understatement, SN850X is very consistent compared to other SSDs, it doesn't really slow down the more full it is either

[Morrie Sells Wigs]

32 minutes ago, podkall said:

decent would be an understatement, SN850X is very consistent compared to other SSDs, it doesn't really slow down the more full it is either

Oh,, well that's good to know.

 

Thank you, for your help and advice.