I bought a GeCube HD 3850 512MB O/C Edition
recently and have generally been very happy with it.
I was amazed at how quiet it is at idle although when left to its own devices it does ramp the fan speed up too much under load. I used ATI Tools to manually set the fan speed and itâ€™s marginally too loud under load and the temps are slightly too high for comfort. So I removed the red cowling and attached a Panaflo 80mm fan using blu-tack and elastic bands and itâ€™s now cool and silent.
Iâ€™m using a Fanmate to reduce the fan speed so that it is silent and the GPU is 40C at idle and hits 80 â€“ 85C at load. I have some headroom with the fan and can turn it up a bit and still retain silence but I havenâ€™t tested it yet.
Itâ€™s a dual slot card and the cooling is more akin to a HD 3870 which is not surprising as the spec is half way between a 3850 and 3870. The copper heatsink compares fairly well against a Thermalright V2; it weighs 230g versus 280g. I think itâ€™s up to the task of cooling a HD 3870 at stock speeds in silence when using an 80mm fan.
My disappointment is that the card idles at its full over-clocked speed of 725/900 MHz â€“ GPU/RAM. Iâ€™ve reduced the speed using ATITool 0.27 and the power consumption remains the same at idle. This suggests that the under-clocking mechanism is likely to be dropping the voltage to achieve the admirably low power draw that the SPCR review measured.
According to a review of this card at Techpowerup
it does support under-clocking so maybe I need to update the BIOS!
This brings me to my only bugbear with these cards which is that there is too much variability in terms of under-clocking in 2D mode, fan speed control and no doubt fan noise. I can recommend them but do your homework if youâ€™re after one with all the features fully implemented; donâ€™t just buy on price.
Note: I used ATITool to down-clock the card and it didnâ€™t affect power draw at all but when I set the clocks back to their default settings the power draw at idle increased by over 20W. I donâ€™t know if this is typical but itâ€™s odd behaviour.