Hi!
The lag and poor performance could both be a hint towards a heavily loaded CPU. Since nothjing besides GParted is running, this wold mean that disk I/O creates this hich CPU load - which in tuirn means that the system has fallen back to PIO mode for IDE transfers.
This can have several reasons:
- the IDE controller reports its own DMA capabilities (and those of your hard drives) incorrectly;
- the IDE driver used for your chipset is buggy or unable to do DMA;
- disk I/O errors have occurred (due to a bad IDE cable or a controller or hard drive failure) - in this case, the system dropc back to PIO since this is the most reliable transfer method.
I think it is best not to disturb the running process (if it is interrupted for some reason, the result is likely to be 100% data loss), so wait until GParted gets the job done.
Afterwards, go back to a text console and issue the following commands:
hdparm -i /dev/hda
dmesg | grep hda
(replace hda with the proper device name for your hard drive). The first one gives you (among other data) the drive's transfer capabilities, including the currently set transfer mode; the second extract from the kernel log buffer all messages about the hard drive you were working on and prints them on the screen. If you had IDE I/O errors, these should be displayed then.