cpu speed

[#1]

I have a gigabyte mb and a sempron 2200 which runs at 1.5 Ghtz.  there are settings on the mb for clock ratio 16 settings ranging from X5 to X12.5 and the cpu clock of 100, 133 and 166 MHz.  Is it safe to adjust these settings (at the momment it is on default)?  If i did change these settings would I notice any diference in performance?

[#2]

The rule of thumb is you are able to safely increase your settings by 10%, but this is overclocking. Overclocking is sometimes regarded as ok, but it's a bit like driving your car around in first gear. Amazing acceleration, but it shortens the life immeasurably. I know people who overclock every cpu they have, but it lasts half as long as people who don't. So the general concensus is do if you can afford to replace it, otherwise don't.

[#3]

If you have never overclocked your CPU before, I suggest you read up on some beginners guides to it.
As Rikaitch said, it can give increased performance but also decrease hardware lifespan.
A quick Google search found this guide.

[#4]

I have found that if you set say the multiplier to a wrong number that the bios will either reset it or prompt you to change it back or load a default. I definitely would NOT change any voltage settings unless you know 100% what you are doing!
Gigabyte offers an over clocking utility for their motherboards called 'easy tune'. In 'easy mode' you are unlikely to come to much harm.
I would definitely enable the temperature alarms in the bios before experimenting and or run 'everest ultimate' so you can see what sort of heat you are generating!

[#5]

is it better to change the settings on the MB or to use the gigabyte utility?

[#6]

The short answer is no, unless you know what settings will work. The utility in 'easy' mode shouldn't make any changes that cannot be recovered from fairly easily, random changes to the BIOS might cause serious problems.

[#7]

Most CPUs are multiplier locked which means changing the multiplier in the BIOS or on the Mobo will have no effect.
What you can do is adjust the FSB (Front Side Bus) but as others have warned, if you try to overclock more than your processor can cope with you could damage your cpu and mobo.
You have to be absolutely sure you know what you are doing before undertaking any overclocking as mistakes can prove expensive.
If an overclocking utility exists by the manufacturer then use that but even they can get it wrong sometimes and cause damage.
All overclocking (where done manually or via utilities) and always at the owners risk..

[#8]

Since you can only overclock by small amounts (10% max) you won't notice any difference anyway.
If you seriously want to speed up your processor you need to think about installing water cooling (yes! it can be done).
Cheaper to get a faster processor or a faster operating system.