What do the different voltages mean?

[Eureka]

So, I'm playing around with the different BIOS settings on my motherboard, and I'm wondering what each of the voltages do. For most of them I understand the basic concepts, but I'm trying to be a bit more enlightened on the subject.

DDR Voltage: Memory voltage.. for memory stability
NB Voltage: Northbridge...?
SB Voltage: Southbridge..?
CPU NB VID: ok... what?
CPU Voltage: CPU voltage... for CPU stability

Those are the 5 voltage options I have, but beyond what I've put down I don't really know what they do and how they affect an overclock. The only thing I know is to turn up the mem and core voltages whenever my system starts to get unstable. But can someone get a bit more in-depth on what these voltages do?

They should really have a sticky for this..

 

[veri745]

VID stands for "Voltage ID", it's a setting that your BIOS uses to set the default voltage.

The voltages in your BIOS shouldn't need to be messed with too much, especially if you don't know what you're doing. A slight bump in Vcore (cpu core voltage) can help an overclock, but increasing the voltage can damage your processor. The same goes if you're overclocking your northbridge. SB voltage shouldn't need any adjustment.

 

[Eureka]

What does bumping each one do in terms of the system? Ram and Core are self explanatory. NB, is that for FSB?

 

[veri745]

If you are running a component beyond its specifications (i.e. overclocking) it may require a bump in voltage to remain functional. If your system is stable, DON'T mess with the voltages. If you are going to overclock your various components, follow the stickies and isolate each component. This is true for the NB and HT, just like it is for Core and RAM. I've never seen anyone give a good reason bump the SB voltage.

FSB is a misnomer on AMD, because the memory controller is integrated, so it really doesn't exist. The bus speed (200MHz default) controls the CPU freq, NB freq, HT freq, and RAM freq, all through different mulipliers.

 

[Candymancan21]

A general rule i have for voltages is dont go beyond 10% of stock. So if your memory says rated @ 2.00v dont go above 2.2v, if your cpu says 1.25v dont go above 1.37v, if your NB says 1.10v dont go above 1.21v.

Of course the voltage's could go higher on certain things and lower on others like for me i wouldnt go above 2.10v for DDR2, but my NB im willing to go to 1.3v, but in general dont go above 10% for cpu's. I dont know what the stock voltage for the x3 and x4's are, i think its 1.32v, so dont go above 1.45v, i know AMD recomends no higher then 1.42vcore http://products.amd.com/en-us/...&f7=&f8=&f9=&f10=&f11=.

VID like someone said is what the BIOS sets the voltage at apon bootup, or what the CPU is programmed to run at on stock. For example some E8400's have a rated VID at 1.25v, others have lower. Mine is rated 1.21v, a thing i have noticed is CPU's with a lower VID (rating) tend to overclock better because they need less voltage to operate at the same frequency

 

[taltamir]

Originally posted by: veri745
If you are running a component beyond its specifications (i.e. overclocking) it may require a bump in voltage to remain functional. If your system is stable, DON'T mess with the voltages. If you are going to overclock your various components, follow the stickies and isolate each component. This is true for the NB and HT, just like it is for Core and RAM. I've never seen anyone give a good reason bump the SB voltage.

FSB is a misnomer on AMD, because the memory controller is integrated, so it really doesn't exist. The bus speed (200MHz default) controls the CPU freq, NB freq, HT freq, and RAM freq, all through different mulipliers.

and on the intel i7 and upcoming i5 (or whatever they call it)

 

[WildHorse]

Eureka,

When overclocking you increase voltages (vcore - voltage to cpu cores, vdimm-voltage to ram, if you use AMD there's an LDT voltage you can adjust (lightning data transport), gpu voltage). The penalty is heat, plus another risk other than heat of the voltage itself gradually damaging components, but usually more slowly than the usable life of the component.

I use a few different temperature monitoring programs and keep a very, very close eye on the temps of the various things as I increase voltages and run stress tests like OCCT and Prime95 Orthos, and other tests that are available for specific components like your video card.

You try to achieve max performance at lowest (coolest) voltages. You also have to pay attention to what the anufacturers say the highest safe voltages are, and also if you live in hot weather maybe dial down your overclocks (reduce heat-genearting voltages) in summer.