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If my write speed is 575 mbps, why does my SSD write at 2 mbps when downloading a vid

Hieveryone

Hieveryone

macrumors 603
Original poster
Apr 11, 2014
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Let's say I'm on a website and I want to download a video.

It is about 3 GB. I have a 30 mbps internet connection.

My write speed on my late 2013 MBPr is like 575 mbps.

But in chrome under downloads it says like 2-3 mbps.

It still only took like 6-7 minutes, but shouldn't it be faster? At least 30 mbps?
 
S

SVTmaniac

macrumors 6502
Jan 30, 2013
417
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Chrome is showing you the download speed in Megabytes per second. Your internet is in Megabits per second. 30 megabits = 3 Megabytes.
 
Intell

Intell

macrumors P6
Jan 24, 2010
18,955
509
Inside
First, make sure you are not confusing megabits with megabytes. Internet speeds are usually rated in terms of megabits. Having the video write to your drive at 2 megabytes per second is about 16 megabits per second. You ISP may not be providing you with the marketed speed due to congestion or peek usage. Resulting in a lower write speed. Or it could be that the source server of the video only has a 16 megabit upload speed and it cannot go faster than that or it could be limited to only be 16 megabits per second.
 
Hieveryone

Hieveryone

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So what would be the point in having a super fast write speed if it is bottle necked by your internet connection? :confused:
 
M

mobilebuddha

macrumors regular
Jan 31, 2008
222
25
so you think the only time that you will use your HD (in terms of reading/writing) is when you are downloading a video?

-_-



Hieveryone said:
So what would be the point in having a super fast write speed if it is bottle necked by your internet connection? :confused:
Click to expand...
 
53kyle

53kyle

macrumors 65816
Mar 27, 2012
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Sebastopol, CA
Hieveryone said:
So what would be the point in having a super fast write speed if it is bottle necked by your internet connection? :confused:
Click to expand...

Internet and download isn't the only reason for write speed. High write speed is good for duplicating files, backing up files (especially other SSDs), working with large photo edits or video edits (although in reality those will see little improvements), anything that writes to the SSD.
 
Hieveryone

Hieveryone

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Apr 11, 2014
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53kyle said:
Internet and download isn't the only reason for write speed. High write speed is good for duplicating files, backing up files (especially other SSDs), working with large photo edits or video edits (although in reality those will see little improvements), anything that writes to the SSD.
Click to expand...

Ok, well I barely do any of that. I don't duplicate anything, backup anything (everythings in the cloud for me), or any photo or video edits.

If I save a word document or something which would be like 1 MB or so that should take 1/575 seconds lol.
 
simonsi

simonsi

Contributor
Jan 3, 2014
4,851
735
Auckland
Hieveryone said:
Ok, well I barely do any of that. I don't duplicate anything, backup anything (everythings in the cloud for me), or any photo or video edits.

If I save a word document or something which would be like 1 MB or so that should take 1/575 seconds lol.
Click to expand...

But your OS does this all the time, every time you open an app, close one, open a new window etc etc the OS is writing cache files, status files etc etc so having the high write speed helps make your machine as responsive as it is. Being able to write downloaded videos at SSD speed won't have even been on the designers radar as previous generations of hard drive could already more than keep pace on the fastest effective download available.

Just because you have a 30mbps internet connection doesn't get you a free upgrade to the entire internet, servers under load (or restricting the speed they will allow a single connection), congestion or a lack of capacity in certain places, faults causing re-routing are all reasons why your download speed from a particular site will be slower.

There is a lot of hardware between your computers drive and the drive on the remote server you are downloading from, your download will only run at the speed of the slowest component.
 
Hieveryone

Hieveryone

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simonsi said:
But your OS does this all the time, every time you open an app, close one, open a new window etc etc the OS is writing cache files, status files etc etc so having the high write speed helps make your machine as responsive as it is. Being able to write downloaded videos at SSD speed won't have even been on the designers radar as previous generations of hard drive could already more than keep pace on the fastest effective download available.

Just because you have a 30mbps internet connection doesn't get you a free upgrade to the entire internet, servers under load (or restricting the speed they will allow a single connection), congestion or a lack of capacity in certain places, faults causing re-routing are all reasons why your download speed from a particular site will be slower.

There is a lot of hardware between your computers drive and the drive on the remote server you are downloading from, your download will only run at the speed of the slowest component.
Click to expand...

But it's very unlikely you'll need more than 575 mbps write speed for those files as they are so small!
 
simonsi

simonsi

Contributor
Jan 3, 2014
4,851
735
Auckland
Hieveryone said:
But it's very unlikely you'll need more than 575 mbps write speed for those files as they are so small!
Click to expand...

The point is, the faster those kind of files can be written, the faster your machine can run. The biggest slowdown in normal running of a computer is writing to disk so if that can be faster, your machine can make better use of the CPU and RAM as it is not waiting for the disk I/O.

Remember what seems "fast" to a human is unendingly slow to a computer CPU.

If you want more detail I'd suggest you do some further reading, there are plenty of good books on how computers work. Suffice to say faster disk read and write speeds are NEVER a problem and ALWAYS a benefit (even before you connect to the internet). :)
 
Hieveryone

Hieveryone

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Apr 11, 2014
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simonsi said:
The point is, the faster those kind of files can be written, the faster your machine can run. The biggest slowdown in normal running of a computer is writing to disk so if that can be faster, your machine can make better use of the CPU and RAM as it is not waiting for the disk I/O.

Remember what seems "fast" to a human is unendingly slow to a computer CPU.

If you want more detail I'd suggest you do some further reading, there are plenty of good books on how computers work. Suffice to say faster disk read and write speeds are NEVER a problem and ALWAYS a benefit (even before you connect to the internet). :)
Click to expand...

I see your point. A lot of people on here say that the Sandisk write spead is 575 while the samsung is 700 but it doesn't make a difference?

I made a video on it actually and it didn't seem to make a difference.
 
simonsi

simonsi

Contributor
Jan 3, 2014
4,851
735
Auckland
Hieveryone said:
I see your point. A lot of people on here say that the Sandisk write spead is 575 while the samsung is 700 but it doesn't make a difference?
Click to expand...

It will make a difference to the CPU but not much of a difference to the human operating it except over time (so certain backup tasks may complete faster etc if the additional speed can be used on say an SSD-to-SSD backup), but in terms of responsiveness both are likely to appear to be equally fast to the user.

Some on here will obsess over such differences but while a normal spinning disk writing at say 80Mbps will obviously see an improvement if replaced by either the 575 or 700Mbps SSDs, the difference between the SSDs will be much less apparent if at all.
 
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