Do I have to defragment or optimize my system?

Definitely! Even a simple defragmentation with the Windows Defragmenter reduced the boot and program start time on average by 20 percent. After optimizing the drive with a third-party defragmenter, this time has almost been halved.

How good is the Windows Defragmenter?

Here one must distinguish between the defragmenter which has to be started manually and the Defrag.exe, that performs it's service invisible in the background. The latter is on par with other defragmenters, concerning the boot time and it also performs well at application startups (Except for TV-Browser). But it makes the last place in defragmentation and the prevention of new fragmentation.

Surprisingly, the Windows Defragmenter does not use any functions of the Defrag.exe, not even the Prefetch files. The only plus points for the Windows Defragmenter is when it comes to actual defragmenting. But it makes the last place in fragmentation prevention, though. It can therefore only be considered as a pure defragmenter, no more and no less.

Is a third-party defragmenter better?

MyDefrag 4.3.1 can be found at the first place on (almost) all the tests, so this question can be answered with a clear "yes".

The second place goes to O&O Defrag 14.1 (where the Professional version was only a tad better) which was only measurably worse than MyDefrag in the most tests.

Choosing a defragmenter for the third place is a bit tricky: Paragon Total Defrag 2010 performed almost as well in the boot time and program start tests as the the other two, whereas DiskTrix Ultimate Defrag 3 was very thorough in defragmenting and increasing the write speed.

Diskeeper is also worth mentioning, since it can prevent most fragmentation before it even happens, but performed only average in other tests.

So which defragmenter should I use?

For pure office PCs the Windows Defrag.exe does it's job thoroughly. Other defragmenters are almost out of place here.

But it looks different when large amounts of data are written and deleted (music, videos, games, etc.). The Windows Defrag.exe does not care about fragmentation and the Windows Defragmenter does not provide satisfactory results when it comes to refragmentation. For this scenario, a different defragmenter is needed!

For those who want a thorough optimization, MyDefrag is the tool of choice. For those who do not need it as thorough and like more colorful, user friendly interfaces are well served with O&O Defrag.