Disk Performance Comparison - Laptop vs Desktop

Posted by JD 07/28/2011 at 18:00

We know intuitively that desktops are faster than laptops – well, most of us know that, but how much faster? I’ve written that video transcoding is 2-3x faster on a desktop than a laptop. Here’s another example where the laptop is slower than a common desktop. You should be able to reproduce this yourself.

Laptop

The laptop used has

  • Dell 1558 Laptop
  • Core i5-M450 2.4GHz CPU
  • 6GB DDR3 RAM
  • 500GB Samsung 7200 RPM SATA HDD (it is the boot disk)
  • Ubuntu Server x32 10.04.3 LTS
    I really like this laptop. It was plugged into the wall during the tests and set to max performance – no power saving.

Desktop

The desktop used has

  • T5XE CFX-SLI motherboard
  • Core i5-750 2.67GHz CPU
  • 8GB DDR3 RAM
  • 1TB WD Black 7200 RPM SATA HDD (not the boot drive)
  • Ubuntu Server x64 10.04.3 LTS
    This desktop was built for $460-ish about 18 months before the laptop was bought. It isn’t anything special. Further, this machine has 3 Xen virtual machines running on it and is actively performing a MPEG2 transcode to h.264 for an HD TV show from last night. The VM virtual disks are located on the same physical disks and the transcode is running on this same HDD too.

Test Program

I had a need to use par2. The DVD player on the desktop was having issues reading an old DVD, so par2 is used to reconstruct problem areas of a specific file. In this case, even that failed, so I moved the DVD to the laptop and read it, which worked without any I/O errors. Still, I wasn’t certain the file was copied over correctly and decided to run par2 with the parity files I keep on every DVD for this situation. Here’s the command used on both systems:

$ time par2 r *2

After the laptop files were verified, the files were copied over to the desktop and the same par2 command was run.

If you have MS-Windows, you can use QuickPar to perform the same tests, but I don’t know how to capture performance data that can be easily compared between systems.

Results

Laptop:

  • real 0m21.391s
  • user 0m9.401s
  • sys 0m3.480s

Desktop:

  • real 0m8.672s
  • user 0m8.510s
  • sys 0m0.150s

The desktop was about 2.5x faster than the laptop based on clock time. WOW! The system time was much higher on the laptop too, which I guess means the IO chip on the desktop motherboard handles more of the IO than on the laptop. That is to be expected. Desktops have more power available.

The disk subsystem of a laptop simply cannot compare to an average desktop HDD.