why change voltages??

[2DividedbyZero]

I am somewhat confused and cannot find a reasonable explanation as to why I should change my card voltages on my HD4870.

Now I have changed them using RBE1.19 and got my 2D 500MHz @ 1.1v and my 3D @ 1.3v

However this does not achieve anything towards an O/C above 830MHz stable which I can get with default voltages ???

Or am i getting this wrong and the voltages aren't adjusted for overclock reasons?

some nice handy helpful chap set me straight please

Steve.

 

[DrPepper]

Increasing the voltage helps you to achieve higher overclocks but sometimes the card can't handle a certain clock no matter what the voltage.

The reasonyou can get above 830 stable is because thats is the furthest that card will go no matter what the voltage is.

 

[2DividedbyZero]

Using CCC I can get the core clock speed upto 990MHz, or do you mean that 830 is just what my card can handle no matter what the voltages are set to?

 

[DrPepper]

Is the 990mhz stable ? Each card is different and can handle different clock speeds. I don't think I could properly explain it but I'l try, Imagine the card is at stock 500mhz for the core speed and the voltage is 1.1. On 1.1 volts you can oc it to 600mhz before it becomes unstable so you up the voltage to 1.2 and you can get 650mhz before it becomes unstable but the even adding 1.3v the card won't oc past 650 it means the card has hit its limit.

 

[2DividedbyZero]

? do some of you really not read the posts?

 

[2DividedbyZero]

why would i overclock my 2D speed when i DOWN VOLT to 1.1??????

i want to increase my3D OVER CLOCK so i upped the voltage to 1.3 (default 1.26ish) but it makes no difference, it is not stable over 830MHz. I thought this voltage thing is supposed to help the o/c????

ahh well, i shall go back to default voltages as they seem not to help any how.

 

[EiSFX]

upiing the voltages sometimes helps in getting a higher overclock but everything has a limit to its overclock and even if you play with the voltages you can't pass that limit cuz that is as high is it still go with stock volts or even uped volts everything has its limits

and upiing the voltages dosen't always magicly unlock the limit of your card and i'm guessing that 830 is the limit of your card with stock volts or even uped volts thats just its limit

 

[2DividedbyZero]

ya 830 it is, back to default v's for sure

 

[2DividedbyZero]

out of curiosity though, what would be considered the maximum I should try and over-volt the 3D to try and reach say 850 stable??? is it possible??? voltage gurus???

 

[D007]

Kind of like overclocking a processor..
some processor cores are very high quality..
some are not..
just depends..
no 2 cards will overclock the same regardless of the voltage.
they all have a top end.
like my processor has a crap top end lol..
even at 1.6 v I couldn't drive it over 3.2 ghz..
just would not do it..
the die wasn't good enough.

other people with the same processor have hit 3.4 ghz, with virtually no voltage increase..
luck of the draw..

 

[nafets]

out of curiosity though, what would be considered the maximum I should try and over-volt the 3D to try and reach say 850 stable??? is it possible??? voltage gurus???

~1.375v - 1.4v aircooled
~1.475v watercooled (possible OVP/OCP may be around 1.46v)

You'll reach a point of diminishing returns (if you haven't already), where increased voltage does not lead to increased core speed. Add to that, the heat output of the VRMs may be unsuitable for every day use and/or 24/7 stability...