New Hard drive for G4 867

I am just wondering if that will improve the performance slightly ? and maybe more important, how ?

A new drive will improve performance to a degree.

Most improvements are gained from the recent technology; larger cache, faster seek times, improved mechanics.

Other improvements are gained with more free space for the OS to use as virtual memory, as well as performance gains that are had just from freshly installing software.

I was under the impression that the hard drive was just storage, and was only used to access

saved files, and when a file is opened ( whether it be an App., Preferences, Documents, etc.. )

the RAM and Processor take over. Kind of like how a car battery works.

Instead of electricity, it is data that is held in stoprage on the hard drive, and the CPU and memory are responsible for processing all that data.

A hard drive is a place to have data written to and read from.

I want to replace the main hard drive ( I have been looking at a 500g hard drive

If your machine is a 2002 Quicksilver or a MDD, then the 500 GB drive is a good idea.

If your machine is a 2001 Quicksilver, it is limited to 137 GB (128 GB formatted) unless you use a PCI card or a specially HiCap driver and partitioning.

Data (all applications, photos, music, documents) are magnetically "written" to the discs of the hard drive.

Software tells the hardware what to do in any particular application.

does clicking on the icon,

tell the CPU to open the data that is written on the hard drive ?

Essentially, Yes.

Clicking on an applications icon begins a software chain reaction process which activates the necessary hardware components and loads the necessary software components for processes necessary to said application.

When you want music played, the data for the song is read from the hard drive, buffered through the memory (RAM is a bus station where data waits to go for processing or be fed to a different component or channel), decoded and processed by the processors, returned through the memory and fed through the appropriate channels in the hardware to be produced as sound.

When music is added to your library, the data is read off a CD, buffered through the memory, processed and encoded by the processors, rebuffered through the memory and fed through the ATA bus to the hard drive, where it is written to disc.

Of course, all of these processes are controlled by software commands, either from the hard drive (in the case of OS and applications) or from ROM (Read Only Memory) chips, which are embedded throughout system components providing root operation coding; this is known as firmware.

Anyhow, there is a lot more to this than the simplistic explanation.

Suffice it to say that a hard drive stores data that is to be manipulated, updated and utilized as a person deems necessary.

Hard drive space is also utilized by the system to store "temporary" commands, files, caches and logs.

This is why it is vital that a drive have free space that is never filled with user data.

OS X needs to have 10 GB free, applications need additional GB's free, and the process of burning a DVD will require an additional 12+ GB free space.

Having 20-30 GB of free space is vital to good system performance.

More is better, as it allows data to be written in closer, contiguous blocks, rather than scattered about (fragmentation) which is detrimental to a system performance.

For an operating system drive, maintaining 40-50% free space is highly recommended, as filling the drive further dramatically decreases the performance of the drive until the system can't move when the drive exceeds 90% capacity.

Less than 10 GB free space is dangerous, with the potential for fatal errors, data corruption and data loss high.