Temperature Hysteresis

so, I updated to msi afterburner 2.0.0 yesterday and when I went into the settings today, I noticed a new header "Temperature Hysteresis". I read the wikipedia on hysteresis and didn't really make much of it, at least not how it would apply to a gfx card...what do you guys think it is, and how would it be useful?

Actually, the wikipedia article does have relevant information, eg/

...For example, a thermostat controlling a heater may turn the heater on when the temperature drops below A degrees, but not turn it off until the temperature rises above B degrees.

Click to expand...

It's obviously more complex with more than two states. There's a post by the dev on how this particular implementation works.

Basically the last temperature to cause a fan speed change is remembered, and no further changes to fan speed is allowed until the temperature rises/falls past the value you set in that option.

herm...interesting... so it's just a delay in spindown/spinup...ok!!!

Yea, so if the temp is changing back and forth 1C, if it's at a change in fan speed spot, it will prevent the speed changing back and forth, which could be annoying.

I have been playing a bit with the "hysteresis" option in MSI-Afterburner and it seems that it works as expected. As shown in figure 1 hysteresis is an "inelasticity" property of the system that prevents it coming back to its initial state after being exposed to some exogenous shock (very different from "persistence", btw). Epsilon is the "inelasticity" measure, which I suspect for this application is system-specific (i.e., cooling system, case, video-card, etc.). I raised the hysteresis parameter in increments of 5 up to 15 and ran Unigine heaven benchmark and MSI-Kombustor. As figures 2 and 3 suggest, there is an inversely proportional relation between the value of the parameter (making more inelastic the response) and the amount of time that takes the video-card to reach its idle/equilibrium temp again.

oooh, that's some good data there