How important is rpm for a hdd?

Hi,
I want to know how much important is rpm in a hdd?
I have seen that some software requirements need specific rpm to run at minimum requirements & all.
How can I check this for my hdd?

Short for Revolutions Per Minute, RPM is used to help determine the access time on computer hard disk drives. RPM is a measurement of how many complete revolutions a computer's hard disk drive makes in a single minute. The higher the RPM, the faster the data will be accessed; for example, if you were comparing two hard disk drives, one with 5400 RPM and another with 7200 RPM, the hard disk drive with a 7200 RPM will be capable of accessing data much faster than the 5400 RPM drive. However, it is also important to note that a 5400 RPM drive will be much cheaper than a 7200 RPM drive.

While it may not be a noticeable speed difference when loading small files, the RPM of a hard disk drive can make a dramatic difference when loading large files and/or several hundred or thousand files.

The higher the RPM, the faster the data can be read from the platters, which increases overall performance.

RPM values range from about 5,400RPM to 12,000RPM and above.

Thanks for replying me guys that was really helpful!
Still don't know how to check my hdd RPM? I guess i need to open my case!