Do you check the total consumption of the computer from the wall? I think my mining farm of 5 Rx 5600 consumes less electricity.
You are doing very well, because you have one video card. When you build a mining farm of 5 such video cards, you will understand what mining on hot video cards is.
Yeah that 71 degree Celsius doesn't look that well especially if it is on an open air rig with just one video card.The fans are low at 58% but I think such a powerful card like the 4090 should be built in a perfect quality so I would normally increase the fan speed to at least 70-75% or at least until the temperature goes to less than 67 degree Celsius.
The profitability if it is only roughly 2600 Satoshi daily or 78000 monthly it is totally not worth mining at that energy power consumption which is near 0.5 Kw and it is 12 Kw daily,not worthy for me,even though I am a partisan of mining at a loss because it is usually in such time that money are made.
I don't have an RTX4090 video card, but if you look at the experience of using the RTX3090, most of the video cards used low-quality thermal pads, and the miners had to change them after 6-12 months. For such video cards, open cases are not used due to overheating problems.