Does Nvidia GeForce GTX 680 getting throttle if temperature exceeded by 70C?

Recently I came to know that Nvidia GeForce GTX 680 supposed to downclock around 705 MHz in case the temperature is going to exceed 70ºC. also I noticed an issue while overclocking the device by making use of non-Adaptive power profile. I set MSI Afterburner v2.2.0 beta to 132% power limit. Also I have set +150 MHz on core clock and +350 MHz on memory clock. The card is running fine at 1,287 MHz on core. The fan speed is increased by 1% for every 1ºC above 40ºC and so far it is not exceeded 75ºC, the core clock is supposed to stick to 705 MHz though I have exited the game. I could not figured out whether it is safety feature introduced that the GPU would underclock as it supposed to hit 70ºC or its just a bug. Any clarification on this particular matter will be appreciated.

I think Dynamic boost feature simply fails and protection clocked is getting down the core frequency of the graphic card to 736 MHz. it seems to be protection introduced on the graphic card. you will be able to get the normal clock if you have restarted your computer.

It seems that protection mode is enabling when clock speed is crossing the power limit. You are making a mistake that +150 add on the mhz when it is on the offset. In the situation of mine I have set +150 and there was boosting on 1310mhz which was sending my card to the protection mode.
You can overclock the card by starting the offset the clock at +100 and memory should be at +200 after that bench with 3DMark 11. After that increase your offset by +25 and again you have to bench. Simply continue with the same until and unless the scores of your begin to drop that means you have managed to figure out that you have got the power limit. Now you should drop the offset by -5 a till the score is getting increased.

As far as I know you will not require to boot your computer to fix the same rather you have to simply close MSI Afterburner or EVGA Precision X whatever you are running on your system. after that restart the same and you will see that clock would begin at 1006mhz.

Well the thing which you have mentioned over here is not happening into the situation of mine. I am getting 80 but so far I did not noticed any throttling. I was bit surprised with the high temperature but it did not cause any issue with the temperature at all. I let you know that I have installed 301 drivers and DX11 3.0 on the system of mine.

In my opinion default fan profile did not seems to be great when overclocking is concerned. I think Nvidia people has to do something in order to balance the cooling and noise. Right now I am using custom fan profile which is giving around 75% and still the fan is quite humming in many situation. I noticed the higher temperature at 1,300 mhz of the GPU clock where 6.7 GHz on memory is around 75c. hence I was bit surprised that you are getting card throttling with70ºC. I think it seems to be really low for today world high-end graphics card which are getting shutdown at 100ºC.

The above mentioned thing does not throttle the graphic card rather it is making benchmarking enough harder.

I don’t think so GPU Boost is not a good feature at least for me. particularly for gtx 680. The people who are running with Vsync will not be able to see card running at overclock clock which you have been set. Normally it would run at the default value. People are used to say why overclock would matter if you are running Vsync as it would cap the FPS to 60. The issue could be caused if you are playing the game at 2560-1600 resolution. If you are going to play game such as BF3 then the extra fps boost would simply break the FPS cap. In case you are using GPU boost feature then this particular card would definitely run on the default clock if you have turned on the Vsync on your card. you should test it out and confirm the same.