vBios and HW modding HD3850

Half a success story on this old ATI/AMD card – a nice RV670 / HD3850 512mb by Sapphire – this came in a pc sold as broken, and got inside a very dusty core2duo build to replace a broken 8800gts 640mb (gonna be reflown soon) that also got a q9450 . The vBios shows a bunch of different voltages avaiable all the way down to 0.974; default has 1.174 as idle (300mhz) and 1.214 as load (669mhz) but even if i create a vBios selecting 0.974 as idle (200mhz) and 1.054 as load (500mhz) voltage, and hwinfo shows these as the voltages being used, the kill-a-watt shows it is not actually saving much if any power wich is just related to the lower frequencies i dialed in. The card is also clocking as high as 830mhz with these voltages selected, so i believe the card actually cannot go lower than 1.174. I left the bios set with 0.974v 200mhz idle (probably not working, just doing 1.174) and 1.174v 825mhz, memory running at 950mhz . This should make for a nice powerful retro / low spec gaming card. Will play BF4 just fine with low textures.
The best feature in this card then is that it actually has fanstop functioning even in the bios menus, so i repasted the card and attached a chipset heatsink on the back, and set the fan to activate at 60c so it would run fanless most of the time.

Also notice the fan replacement on the CPU cooler / no cleaning could make it run silent so i swapped for a regular 120mm fan.

hd3870 heatsink

Leave a Reply