8800gt dynamic fan settings

[rhiridflaidd]

Instead of manual profiles, rivatuner allows you to change the hardware settings of the ADT fan controller.

You need to set Autofanspeedcontrol =3 in the registry of rivatuner and don't ignore rivatuner's sensible caveats.

(Correcred following mackry's post)

Using Rivatuner you'll find that

Dutycyclemin 29
Dutycyclemax100
Tmin74
trange32
toperating90
tlowlimit80
thighlimit100

This means - min fan speed 29 -
max 100,
temp it starts ramping up the fan speed
How quickly fan speed is increased in response to a higher temp...

My settings are -

Duty cycle min 40%
Max 100
Tmin 36
Trange 20
Toperating 90
Tlowlimit 0
Thighlimit 100

So I'd recomend most people to change the defaults.

(Some of you might not have earplugs and might not want to run 100% speed - or if you have an aftermarket cooler plugged into the Gt's fan headers, you might want different settings.)

If you want to make up your own settings, the tricky part is that there are 2 critical points - the bottom point is easy - the temperature at which you want the fan at default speed - I choose 36 degrees and 40% fan output.

Then you need to decide at which point you want the fan to spin at it's maximum. I choose 56 degrees, but you can't eter that value. You have to play with the Trange, and with Tmin and duty cycle min to get this value right.

You can play manually or whip out a spreadsheet.

To set up the spreadsheet
b1= dmin,
b2 = dmax,
b3= tmin,
b4 trange (which can only be in hard steps of 20,26,32,40)
b5= (The temp at which you want full fan output.)

in cell B3 ( tmin) enter this formula ==B5-((3*B4*((B2-B1)/100))/2)

This sets t min at a level where the fan hits your desired maximum at the value you set in b5.

Then mess around with dmin and d range until you get values that makes sense.


I set up the numbers 1-100 in a spreadsheet and used this formula

=MIN(($B$2),MAX(($B$1),(C1-$B$3)/($B$5-$B$3)*((($B$2-$B$1)))+($B$1)))

to calculate the fan output for every temperature. (C1 = 1 degrees- carry on to c100)

I hope this makes sense. It is unverified, so mess with these settings at your peril unless you are happy to take the risks of changing the (rubbish) default fan settings.

And you need to go to rivatuner and set the value to 3 in expert settings. Unless you can work out shich ini setting in rivatuner to change, i'd wait untill all the above is verified - just in case of problems.

I didn't post my spreadsheet because you'd be nuts to download a spreadsheet from a newbie! If anybody wants to take this further, feel free. I don't have the time and will be putting on a waterblock soon!

NB the temps are what the ADT controller temp measures, and not the core temp measured by default in rivatuner, and ati tool etc. So this measures 5-8 degrees cooler than the true core temp. You need to enable the ADT plugin to keep an eye on this temperature to monitor the results of any changes, then setup... on core temp, and choose the ADT temp instead of default

NB2 After upgrading graphics card drivers you need to re-enter the values in rivatuner.

 

[yacoub35]

Thanks, will try this out when mine arrives. No other replies yet? Anyone else fool around with this yet?

 

[mackry]

Upload your spreadsheet or elaborate more Your cells are either incorrect or something because the formula dont match up

edit: or make a guide with screenshots

 

[rhiridflaidd]

I wouldn't download a spreadsheet off a noobie! (general priciples!)

Sorry about the unclarity - the value previosly needed to be in % for fan output. I've changed the formula to use round numbers.

=B5-((3*B4*((B2-B1)/100))/2) gives the dmin value