Parallel downloading is one of the experimental features of Google Chrome that is often recommended to speed up downloads. This guide explains what parallel downloading is and how to enable it in Chrome.
Content
- What Is Parallel Downloading?
- How Parallel Downloading Can Speed up Downloads
- How to Enable Parallel Downloading in Chrome
What Is Parallel Downloading?
Parallel downloading – or multithreaded downloading – is a method that significantly improves download speeds for large files. It works by breaking the file into smaller segments, then downloading these segments simultaneously, using multiple connections to the server. Once downloaded, the segments are reassembled in the correct order.
It maximizes your Internet bandwidth utilization by avoiding congestion on your end and possible limitations/restrictions at the server’s end.
How Parallel Downloading Can Speed up Downloads
The parallel downloading feature won’t magically increase your download speed beyond your Internet plan. It increases download speed efficiently, using the available bandwidth. There are many possible limitations and bottlenecks on both the download server and your network’s end. For example, congested server/network, packet loss, bandwidth limits by server, and server queue.
Parallel downloading can bypass the following situations to speed up downloads:
- On a congested server, decreases the burden on a single connection path that could lead to slowdowns.
- A single connection won’t fully utilize the available bandwidth, as many variables can hinder data transfer, such as protocol overhead, data flow fluctuations, data request delay, etc. With multiple connections, other connections can use the spare bandwidth for optimal bandwidth usage.
- In the case of packet loss, the download process won’t be stopped/delayed, as the other connections will continue to download other parts of the file, while the dropped packet is retransmitted.
- It can circumvent server-imposed bandwidth limits per connection by using multiple connections.
- If a server is congested, it may put requests in a queue to minimize load. With multiple connections, there is a higher chance of being first in the queue to continue the download process with minimum delays.
- High latency to the download server can slow down overall download speed. Multiple connections can allow multiple packets to be sent/received, which can improve download speed by sharing wait time for single packet confirmation.
Overall, parallel downloading speeds up downloads by optimally using available bandwidth and avoiding server/network issues that could delay the download.
However, keep in mind that parallel downloading can also slow down the download speed for small files – usually under 5MBs. It adds extra overhead to the download process when it creates segments, establishes multiple connections, and reconstructs the file. For small files, this overhead can be slower than the actual file download time.
Parallel Downloading Speed Test
To see this feature in action, I downloaded the 329MB GIMP setup file. My Internet speed is 30Mbps, so theoretically, 3.75 MBs/s is my maximum achievable download speed.
Note: I started counting when the download file appeared in the Chrome download history and stopped when it became available to execute. I also deleted browser data after each test.
Parallel downloading disabled: it failed on my first attempt, and I had to restart. On the second attempt, it took 2 minutes and 41 seconds to download. The download speed fluctuated between 2.0 MB/s and 2.7 MB/s, with the highest spike being 2.9 MB/s.
Parallel downloading enabled: it took 1 minute and 54 seconds to complete. It fluctuated between 2.5 MB/s to 3.1 MB/s, with the highest spike being 3.4 MB/s. It did dip to 1.8 MB/s for a few seconds but quickly stabilized to above 2.5 MB/sec.
I won’t say this experiment proves parallel downloading is the best choice, as too many variables can affect the outcome. However, if you usually download larger files, parallel downloading will surely be beneficial.
How to Enable Parallel Downloading in Chrome
If you are ready to take advantage of parallel downloading, enable it in Chrome from the Chrome flags. These instructions will work on both the desktop and mobile versions of the Google Chrome browser.
In Chrome, type chrome://flags in the address bar, and hit Enter.
Type “parallel downloading” in the search bar, and select Enabled from the drop-down menu next to the Parallel downloading flag.
Restart the browser for the changes to take effect.
Personally, I have parallel downloading enabled on both Chrome and Opera (Chromium-based). I have to download work-related apps often, so it’s quite beneficial for me. For people seeking more control over parallel downloading, I recommend using a dedicated download manager instead.
Image credit: Canva and Google. All screenshots by Karrar Haider.
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Karrar Haider –
Staff Writer
Karrar is drenched in technology and always fiddles with new tech opportunities. He has a bad habit of calling technology “Killer”, and doesn’t feel bad about spending too much time in front of the PC. If he is not writing about technology, you will find him spending quality time with his little family.
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