Slowdown after adding another hard drive

This is mostly a post geared for computer enthusiasts and system builders.


As it turns out, when adding another hard drive, in many cases, the motherboard has a tendency to slow down after adding the hard drive. There is nothing physically wrong per se with the hard drives but the motherboard would not boot as quickly. In my case, my motherboard, and MSI X99A XPower would hang for a bit with the Error Code 99, then boot as normal. It also took longer to get input in after the Windows log-in screen appeared. However, often with just a bit of work, this can be addressed.

This may sometimes be fixable. Swap the order of the SATA hard drives.

  • SATA 0 should always be the first hard drive that you boot into the most
  • SATA 1 likewise should be either the OS that you use the second most (ex: if you dual boot) or storage
  • After that, you should first put in any hard drives that have operating systems then storage


After putting in the hard drives, you should go into the boot section of your motherboard’s BIOS and change the boot order:

  1. If you have any medium that you boot from like  USB sticks or DVD drives, put those first
  2. Next should be hard drive – actually, you could use only the hard drives if you don’t mind f changing the boot order  each time that you put in a new drive
  3. Be sure to check whether you are in EFI or regular boot mode and select accordingly in the BIOS

Still in the BIOS and the boot options, within the hard disk storage options, you will have a few options on which disk:

  1. The SSD or hard drive with the boot installer (Ex: GRUB) should always be the first disk
  2. Any operating systems after that should be next
  3. Turn off any physical drives used for storage

Save and exit the BIOS. You should be back to normal boot times.


In some cases, you may need to clear the CMOS of your motherboard (use the jumper, the button, or pull the CMOS battery and unplug for 30 minutes).  Most motherboards though, should not need a CMOS clear. I actually think now that a measure of a good motherboard has been how little I have to clear the CMOS. So far the MSI X99A XPower has done a good job for me. I am currently using the A20 BIOS.


It does seem like adding more drives does make motherboards slow down in terms of POST time, but it should never be by much. If you do encounter this situation, try some of the tricks I’ve recommended and with a stable BIOS, you will see the POST times almost the same with just 1 drive.

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