iMac keeps needing SMC resets, won't sleep

[jhelzei]

Macs Fan Control is doing quite a good job at keeping my mid-2007 iMac from overheating, but I've run into a couple of issues that concern me. Firstly, my iMac won't sleep properly any more. The screen will go to sleep, but the fans keep pumping out air at high speed and the computer generates quite a bit of heat. Secondly, and more urgently, my iMac won't restart properly after a full shutdown. I'll shut it down for the night, and the next day it will not power up. So far, an SMC reset (unplugging power cable for 15 seconds) has always resolved this - i.e., the Mac will then boot up properly.

Any suggestions? Should I uninstall the software?

Note: I also have a program called Temperature Monitor running to monitor the other sensors in my iMac.

[Steven]

jhelzei
1. Try uninstalling Temperature Monitor first and reset SMC once again
it it doesn't help,
2. Try setting all fans to Automatic control.

And tell us the results.

[jhelzei]

I've removed temperature monitor, reset the fans to auto and reset the SMC one more time. However, I think you can see from my screenshot the problem. With Automatic fan control, the temperature of my GPU Diode is nearly 100 Celsius, which seems way too hot. These temperatures are not from gaming, but just normal web browsing. If I try to play a 3d game, the temperature can hit 130 Celsius. I have to keep the fans cranked higher, otherwise I'm afraid my GPU will melt. Any other suggestions?

[Steven]

jhelzei
what about sleep/restart issue now?

PS. try to set constant 2000-2500 RPM value to ODD fan

[jhelzei]

jhelzei
what about sleep/restart issue now?

PS. try to set constant 2000-2500 RPM value to ODD fan

So far I haven't needed to reset the SMC. However, sleep continues to be a problem. Setting the ODD fan to 2400 rpm didn't keep it cool enough, so I've set both ODD and HDD fans back to GPU Diode controlled and the CPU fan to 3300 rpm. Should I avoid controlling fan speed with another sensor, or just use constant rpms?

[Steven]

Try setting all fans to auto and check the sleep issue.