"Overclock" Harddrive

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Just yesterday I was accidently in the Bios of my Laptop and I found out that my Harddrive is set on Pio Mode-4/UDMA Mode-2.
Now I went to the homepage of the Harddrives manufacturer Toshiba and looked up my HD (Model: Toshiba MK6014MAP).
The "manual" said:
6.0 GB
13ms Avarage Seek Time
ATA-4 Interface
66.7 MB/s Ultra DMA Transfer Rate
1,024 KB Buffer
....
Under functional specs it said:
....
Rotational Speed: 4,200
Data Transfer Rate:
Max. Internal: 193.9 MB/s
Buffer to Host:
ATA Pio Mode-4: 16.6 MB/s
UDMA Mode-2: 66.7 MB/s
Buffer KB: 1,024

Now I would like to know if I could set the UDMA Mode in the Bios to Mode-3 or Mode-4 without damaging the disk?
I thought it better to ask before trying it and damaging my data or even worse the disk itself.

Here the link to the manual: http://www.toshiba.com/taecdpd/products/pdfs/mk6014.pdf

[daveleau]

This is not really overclocking. Often the default setting is for PIO. DMA is much more desirable. You cna switch without damaging your hdd or any other component and the switch is reversible.

PIO= programmed I/O...calls on the cpu for every I/O function
DMA (UDMA)= direct memory access...bypasses the cpu and puts data directly into RAM for cpu use and gets rid of this specific bottleneck

Dave