My idle temperatures jump from 43 degrees to sometimes around 70. Voltage is at 1.5. This is default/auto managed OC. Is that normal and or safe?

70 is not bad as the thermal point is around 100C. I assume the temps go up during intensive use such as gaming or video editing, etc.

The temps would jump from 40-70 just while I turned my PC on and watched it idle. As for the 1.5 Voltage, that just seemed rather high. I changed the settings a little and now it's down to 1.3 Voltage, same 4.8 GHz speed. But after running Rust and testing, I lost 30-40 FPS. Using the AWCC I can't increase the Voltage back to 1.5 to test if that was why my FPS was so much higher though. I'm kind of lost here now. 

1.5 Volts is too high. You are lucky it did not do any damage to the CPU. 1.35 to 1.4 Volts is the maximum recommended unless you have really good cooling and VRM control. If you are doing this on an Alienware system I would not recommend using such high voltages at all.

My advice would be not to overclock unless you understand what you are doing. There are good guides on the internet.

So I'm currently using 4.9 GHz in AWCC, 1.33 Voltage, and -50 mV offset. My idle temps when I turn my PC on are around 50-60, and sometimes spike to 70. Is that normal? I've read other posts where people get idle temps of 35-40. So I'm assuming there's an issue somewhere. 

Some more information, I'm using Ultimate Performance mode for power. Thermal is set to Performance mode. Would that explain why? 

Yup 1.5v is critical !!! I run a 5.0 OC in AWCC and stable at 1.35-1.38v and set my cpu rad fan one speed and that is a thermal offset manually @ 49-50%. If your gonna overclock don’t use fan curves !

Also when I called Dell Tech support on the phone, the guy who answered said those temperatures were fine as well as 1.5 Voltage. Said that was within the limits. Though even I thought that was a bit excessive. I figured out that it was because I had it set to ultimate performance. Now I'm getting lower CPU frequencies instead of being maxed out the entire time. So it spikes from 1.2 GHz to 4.8 GHz. Keeps the temperature down. Voltage jumps from 0.5 to 1.3. Seems to be better with balanced power mode as opposed to Ultimate Performance. 

I just use Auto  and let it figure out the voltage and offset voltage. I never mess with that I try to stay in the low yellow then test save and name the profile. I also only overclock for gaming and when im not game my default settings are on balance modes. Thermal Balance and Power Balanced.

HighPerformance when gaming with Thermal Offset fan Profile on 1 speed.