I decided to change from SCSI to IDE, because IDE is simply better.
Are you joking? And no wonder why you experienced a speed increase in some areas, considering that you compared a very old 4gig with a brand new ide disk. Not only is scsi faster, but the disks are usually way more reliable, which is one of the reason for the higher price tag. Professionals usually use scsi for this very reason and the fact that it gives much better perfomance, especially when it comes to multitasking. The fact they run hotter, is because they spin much faster due to them having higher perfomance.
I would like to see a high end web server using ide under alot of load... You are damn lucky if you get a few years from a modern ide disk before it starts failing.
I use ide/sata in my pc only because i am poor and need alot of space.