I work with two desktop PCs of different configurations(one at home and other at school). I made a live usb with persistence using ubuntu 19.10 so that I can operate on both Pcs with common applications installed in the persistent usb folder. I used a usb 2.0 to make the live usb. I find that the speed of booting and general speed to be sluggish. I have two doubts as follows:

  1. Will creating a live usb with usb 3.0 improve general speed significantly? Both my PCs have usb 3.0 ports
  2. Is there a better alternative to live usb with persistence for my application. All I want is to run a usb bootable Ubuntu with some common applications on both the PCs. I do not have an internet connection in my school PC, so I update the required applications using my home PC which has net connection. That is why I went for live usb-persistence mode
  • 1
    Regarding speed improvement: USB 3.0 can be significantly faster than 2.0, but you should look at benchmarks before buying a 3.0 flash drive. In the early days of USB 3.0 there were drives that were faster on a 2.0 port because the 3.0 implementation was poor. The same applies to USB 3.0 ports: some older mainboards have horrible transfer speeds because of poor USB 3.0 hardware.
    – danzel
    Apr 17, 2020 at 6:36

2 Answers 2


Full Install USB vs Persistent install

A Full install USB and a Persistent install USB both save data and installed programs after reboot.

Comparison between Persistent and Full install USB

Advantages of a persistent install:

  1. You can use the persistent pendrive to install Ubuntu to another computer.

  2. A persistent install takes up less space on the pendrive.

  3. You can reset the pendrive by overwriting the old casper-rw file with a new one.

  4. The install to pendrive takes less time.

Advantages of a Full install:

  1. You can update and upgrade.

  2. If you have problems or wish to modify, the solution is the same as with an internal install, (You can ask for help in these forums).

  3. No ugly startup / install screen.

  4. Better security, you can use full encryption

  5. You can use proprietary drivers.

  6. Hibernation works.

  7. A persistent install is limited to a 4GB casper-rw and a 4GB home-rw persistence file, to get more persistence requires persistence partitions. Once casper-rw is full, the drive will not boot. YUMI and Universal can use persistent files greater than 4GB when installed on a NTFS partition and in BIOS mode. Ventoy can also use persistent files larger than 4GB.

  8. Faster boot.

  9. You can run VBox and use virtual machines.

Note that once booted, both methods run at about the same speed.

Full Install Method

One method for creating Full install USB: How to Create a Full Install of Ubuntu 20.04 to USB Device Step by Step

  • If i do a full install on a USB from one PC , will I be able to run ubuntu from the same USB on another PC. Actually I am more looking at using the usb interchangeably between two PCs
    – Jaivishnu
    Apr 17, 2020 at 5:49
  • @Jaivishnu : There is no problem running a Full install on multiple PC's as long as no proprietary drivers are installed. Apr 17, 2020 at 5:56
  • OK. Will using a usb 3.0 help in improving general speed or USB 2.0 is still sufficient
    – Jaivishnu
    Apr 17, 2020 at 6:26
  • @Jaivishnu: I believe that lots of RAM is better than USB3 as Ubuntu seems to run in RAM when available. If you don't have more RAM than the amount of data on the USB then USB3 is definitely better than USB2. Apr 17, 2020 at 6:44
  • I am trying to follow your steps to do the full install. Can you pls clarify why the following last steps are required. Copy the boot and the EFI folders from the Live USB to the boot,esp partition sdx3. Copy grub.cfg from partition sdx4 /boot/grub/ to partition sx3 /boot/grub/. Re-Install grub: sudo mount /dev/sdx3 /mnt sudo grub-install --boot-directory=/mnt/boot /dev/sdx
    – Jaivishnu
    Apr 17, 2020 at 7:29

Speed of USB drives

Some USB 3 pendrives are much faster than USB 2 drives, but the speed varies a lot between different makes and models. You should check carefully what to buy.

If you can afford it, please consider an SSD connected via USB 3, either directly or via an external box or adapter. That way you get almost the same speed as with an internal drive.

See the following link and links from it,


Edit: An SSD with SATA interface and an external box/enclosure or adapter do not cost more than some higher quality pendrives of similar size, and I think such an SSD performs much better. The only disadvantage is that it is more bulky so it is more convenient to use a pendrive.

  • 1
    Do you find any difference between different types of drives when there is lots of RAM? I think the first time a program is opened takes a little longer but the second time is just a flash. I know USB3 or SSD is much faster if the OS is running on swap space. Apr 17, 2020 at 8:44
  • @C.S.Cameron, What you say is true. But a better drive (faster and more durable SSD or high quality pendrive) not only (1) boots faster, it also (2) writes much faster (3) continues to write faster (4) lasts longer before failure. My own experience is that these things make a difference also when there is a lot of RAM. -- The point 'lasts longer' is most important with installed systems unless they are tweaked, but those tweaks cost stability of the file system.
    – sudodus
    Apr 17, 2020 at 11:10
  • I mostly agree with what you say concerning, (more expensive), SSD's, but some people might be disappointed if they expect a huge improvement with a budget USB3 flash drive. Apr 17, 2020 at 12:32
  • @C.S.Cameron, Some pendrives are advertised as USB 3, and probably the interface is USB 3, but the internal electronics including the memory cells are not much faster than what you can find in USB 2 pendrives. For that reason it is important to check carefully what to buy, if you want fast writing, particularly when writing 'many small files'.
    – sudodus
    Apr 17, 2020 at 12:37
  • Yes, The good ones seem to cost four or five times as much. Apr 17, 2020 at 12:43

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