Hi

Why is it necessary to change CPU core voltage? Is it done only when overclocking?

It runs more stable but increases the
chances of frying the cpu.

LONG LIVE LINUX!!!

if if OC your processor too much it's gonna become unstable. you can make it stable by increasing the VCore. Be aware that raising the VCore makes your temps go up

The official reason is because different processors use different voltages, like the original Pentium and the MMX Pentium. But it is probably used for overclocking most commonly, but as was mentioned going to high will destroy your CPU.

Actually, in this day and age of processors that run between 750 and 1500 Mhz. at pretty low cost, it is no longer "necessary" to change the cpu voltage.

Overclocking stems pretty much from the days of 100 to 500 mhz. processors, where an extra 25 to 100 mhz. would actually make a difference sometimes, between the cost of upgrading - or not upgrading. Many mobos back then were only able to run speeds such as 100 - 266 mhz. A lot of this has to do with the mobo manufacturer too, because they stand to make a lot more money as well, if they keep having people upgrade often. If you wanted 300 mhz. speed, you had to change your board. Then, if you wanted 550 or better in speed, you often had to change your board again - and often the processors as well.

And that's where overclocking began . . .
With people like us techies who dream about computers that'll clean our house and make our coffee - to see how far we can push those mobos and processors WITHOUT having to constantly shell out more money.

Technically, a mobo could easily be developed that has all of the FSB settings, two or three different sockets, and clock multipliers that range from 1x to 20x. But then the mobo manufacturers would sell way fewer boards.

But like I said earlier, overclocking or "tweaking" has never ever been necessary. People do it out of curiosity, and to see what they can squeeze out of their systemv - knowing in advance that the risks can include a fried processor which will not be warranted. So, to put it in a nutshell, I guess overclocking in this day and age is strictly an "ego thing" anymore.

If you have a totally limited budget, or if replacement components are just not easy to obtain for you - then just don't do it. It's as simple as that.

Hey Intel, AMD rulez!

I am not sure I agree with the last post. CPU voltage core changing is very necessary for overclocking and overclocking is alive and well in these days. 750 - 1500? I started my latest machine at 1800 and I still overclocked it. Nothing wrong with getting free speed. You just gotta do it right. You have to start with building and buying your own components. You buy the right stuff and the sky is the limit. For example, my modest overclocking machine that I am upgrading to a serious overclocker, is running at roughly 2600Mhz from 1800Mhz P4. That is an 800Mhz jump, and the 1.5V that I moved the CPU voltage up made it all possible. Without any voltage modification, it was only possible to get 400Mhz of change out of it. My next change is going to be a new motherboard and some Xtreme Memory Speed from Corsair, and I expect to hit 2800 to 3000Mhz. Out of a 1.8A, that is up to 1200Mhz of change. Of course, dont take my results and try to make them into yours, I have done some research, and buying the right components off the bat is the major difference. My next board will do 1.85V which is .3V higher than stock. .3V!!! we are not talking huge changes here. But it is the difference between stable and not... Of course, I am using a water-cooled system to do it. My processor runs at 32 degrees Celsius at boot and 33 Celsius when stressed! 30 degrees is ambient. You can never have too much speed. Here are my specs and prices at time of purchase:

Antec Black Mid Tower Case (120)
P4 Northwood 1.8A (175)
MSI 645 Ultra (69)
Corsair 2700 Cas2 (175)
Custom Built Water Cooler (150)
PNY TI4200 64MB Overclocked (175)
Quant. 2 WD 120GB 8MB Cache (150X2)
16X DVD (70)
32X CDRW (100)
SB Audigy (90)
LS-120 (75)
Intel NIC (75)
-------------------------
1575 over time for a 2.6 GHZ machine and will be a 2.8 or higher... with another 150 dollars. 2000 dollars with monitor is not bad for computer that runs circles around most other computers, especially some retail brand machine...

And to give you an example of how much money you save just on Processor alone, Pricewatch lists the 1.8 at 144, the 2.53 lists at 448 dollars. 304 dollars more! For another 40 dollars, I bought the water-cooler, motherboard, and case to put it all in. Overclocking is so worth it if you just plan it out.

My post was for "joe ordinary" who knows little to nothing about overclocking.

Most "joe ordinary" type of folks, will be perfectly content with the speed of a 750 to 1500 Mhz. processor. I'm a TOTAL power user, and I know that I'm perfectly content with my totally tweaked out, but NOT overclocked 1.2 Ghz. machine. I perform so many professional functions on my machine so often, that I've had people watch me and shake their head at how fast everything works. And I do mean - FAST . . .

GAMERS on the other hand, often tend to push their machines for every shred of power that they can glean from their machines, in order to makes games run faster, smoother, whatever.

But like I said, my post was for most average people out there, primarily ones who know little to nothing about souping up the hardware on a computer. Although I grant you that you can soup up any computer hardware under the right conditions, with the right amount of knowledge, and the right amount of money. But again, that doesn't apply to most people.

Hey Intel, AMD rulez!