All new drives have bad blocks. I would "zero-out" the drive to re-allocate those bad blocks and re-install the OS. I would also boot from the installation CD and install the OS with the drive inside of the machine. Installing to an external USB or Firewire enclosure is not as fast as as SATA2 data transfer speeds. Also when a drive is new and has a fresh install of OS you must let Spotlight completely index the drive before using it or trying to open applications. If you try to access the drive while spotlight is indexing the drive will get this type of performance hit. Also, remember that the drive will get faster and faster as you use it.
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All new drives have bad blocks. I would "zero-out" the drive to re-allocate those bad blocks and re-install the OS. I would also boot from the installation CD and install the OS with the drive inside of the machine. Installing to an external USB or Firewire enclosure is not as fast as as SATA2 data transfer speeds. Also when a drive is new and has a fresh install of OS you must let Spotlight completely index the drive before using it or trying to open applications. If you try to access the drive while spotlight is indexing the drive you will get this type of performance hit. Also, remember that the drive will get faster and faster as you use it. After you install the OS and boot up, notice the little dot in your Spotlight Icon...this is telling you that Spotlight is indexing the drive. You must NOT use the machine while this is in motion. Let Spotlight do it's thing and then use the machine as you normally would. You will see how the boot-up times decrease and performance increases as you use the machine more. I doubt very much you got two bad drives in a row. Try my recommendations and be patient.
All new drives have bad blocks. I would "zero-out" the drive to re-allocate those bad blocks and re-install the OS. I would also boot from the installation CD and install the OS with the drive inside of the machine. Installing to an external USB or Firewire enclosure is not as fast as as SATA2 data transfer speeds. Also when a drive is new and has a fresh install of OS you must let Spotlight completely index the drive before using it or trying to open applications. If you try to access the drive while spotlight is indexing the drive will get this type of performance hit. Also, remember that the drive will get faster and faster as you use it.