i have a windows xp installed on drive c. and all programs installed on d:\program files. Somebody said it will slow down the system. it that true? Should i install programs on c:\program files? if it's true, why?
If your primary drive is an SSD, and your 2ndary drive (e:) is non SSD, you would technically slow it down (ie have slower access to your software, not the OS), otherwise no, you will not slow it down. If anything you might have a minute increase due to putting the software on the 2nd drive (additional read/writes)
The answer is it probably isn't slowing anything down. However, there are a lot of qualifying statements that need to go along with that. Jakub gave a good example of a case when it could slow it down.
Another case where it would be slower is if your D volume is on the same physical drive as C, and suppose your C partition is barely filled (and massive), with D being towards the end of the drive. This could cause a performance hit as many magnetic hard drives (non SSDs) have slower io times when accessing storage locations towards the end of the drive.. I mean quite a bit slower too. It depends on the drive of course. Still, that should be a minimal effect.
Is your D partition/volume on the same physical drive as your C? If not, in all likelihood, you're probably experiencing a slight performance improvement.
Did this person who said it would slow down the system qualify by what rationale?