I have a EVGA GTX460 in a spare Celeron motherboard running Windows 7. It is setup for folding. I was having EUEs on my main machine, so I wanted to try the card on the spare setup. It is now running OK. I am running GPU-Z. I have previously noticed some variation in the VDDC value when I have tried different GFX cards in this setup. I assumed that it stands for VDD core, although some google searches suggested that it measured current (perhaps it works differently on an ATI card?). Since I wondered whether the EUEs on the main machine might have been caused by the PSU not supplying enough voltage/current, I was interested to look at this value. -> I now see that it varies depending upon what the card is doing. 2D desktop, low power VDDC is around 0.875V. 3D "folding" high power, VDDC is around 1.01V. I can understand that if the GFX chip isn't doing much, it is probably safe to reduce the chips power supply voltage to save power dissapation (low voltage during underclocking?). Has anyone else observed this? Is this normal?
The VDDC variation is completely normal, it simply reduces the voltage when it isn't doing any demanding tasks in order to save power and is nothing to worry about.
