Advice about undervolting

it will extend the life of your equipment.

as for how much... that is up to the pc gods.

1--no

2--every cpu is different so you would need to find that out by trial and error

3--dont know--cpus should last a while--you would probably upgrade it before the end of its life span

I did the same thing with my 955 because the first summer after I built my system I didn't have air conditioning. Just like overclocking, there are no magic settings that work for all chips since they are all ever so slightly different, you have to do some trial and error. I was able to get my 955 down to about 1.25 V at 3.2 GHz, I didn't try to go any lower.

In the review tom's did a few years back they got it down to 1.152 V and were able to keep it stable at 3.2 GHz so it really depends on your chip and how long you are willing to work at it.
http://www.tomshardware.com/reviews/undervolt-cpu-pheno...

All suggestions above are good ones!

Under-volting coupled with underclocking will definitely lower temps and thereby prolong the life of electronics. This would be good during the hotter months in summer.

thank you all very much for your replies
and I just want to know one more thing
Will Undervolting Reduce Performance

If you keep the clock speed the same the performance is identical, the voltage has no effect on the performance of the CPU. If you reduce the maximum clock speed while you are undervolting to further reduce power consumption your performance will also be reduced.