Hmmm, slight difference to what I'm seeing on my systems of the era.
Dynamic/Adaptive/Offset voltage if I'm correct (Certainly on the Asus and Gigabyte boards of around that time and generation), is letting the CPU call for voltage from its own set of VID tables and call for the appropriate voltage for that set speed you've got it at.
For example, my i5 3570 calls for 1.28v from its VID table for 4Ghz. And calls for 1.14v from its VID table for 3.8Ghz. And so on.
This is the voltage that the motherboard will try and supply it from the PSU.
Then, when you set a dynamic voltage or adaptive voltage, depending on what amount you set, it adds or deducts from the VID that is called.
So as my i5 3750 calls for 1.28v and I am running it at 4Ghz, but I know it can run at 1.08v, I set the adaptive voltage to -0.2v. So when the CPU turbos and calls for 1.28v to hit 4ghz, it also applies the -0.2v to make it 1.08v instead.
But as this applies the voltage to all of the VIDs the CPU calls, it also means its low power 0.9v VID at 1.2ghz, gets a -0.2v as well. So it actually sends the voltage down to 0.7v to the CPU when at idle uses. Not all CPU's can take this and some will stall the system. So you need to adjust the voltages so it's increased or reduced and suitable for its highest active state and the lowest too. (eg, -0.19v instead of 0.2v)
That's how it works on the older systems from my experience (I have two such systems right now, i5 3570 with a Gigabyte Z77-D3H, and a i7 4930k and Asus RIVE, both using adaptive voltage/dynamic voltage).
There is a further one that is more advanced in the BIOS, that's supposed to adjust the voltage when the CPU goes Turbo to the voltage amount you list; or the Turbo Voltage. But this appears to have been partially broken since Windows 8 and so doesn't really work properly from what I understand.
In your own examples there, that +500mv will send 1.8v (or whatever the motherboard limits it to, but assuming there is no cap set up inside the motherboard, then yes, you get 1.8v) into the CPU. Which (in theory) will fry the CPU.
Unless if I'm using dynamic/adaptive/offset voltage wrong here, I would pull the voltage back on that dynamic/adapative/offset voltage.
:: edit ::
Taking a gander at other pages, it appears dynamic/adaptive voltage is a specific name for the broken Turbo Voltage (I had a thread here a while back asking about it, it's called Additional Turbo Voltage on the Asus boards) that I'm talking about on the third to last paragraph. But its effect is the same as I listed in the second to last paragraph; Only instead of adding it to all the VID voltages, it only applies it when Windows sees it as going Turbo (which it doesn't seem to have a set way to doing so, which is probably why you're seeing it in gaming but not benching). So you will still get 1.8v going through when it thinks its going at max speeds. It won't look at it and go, I only need x amount (1.485v), it'll apply all of it. So I would still recommend you keep it low.
:: further edit ::
So, what's supposed to happen (it does, but that's another story), is that the BIOS is supposed to know when the CPU is using its Turbo, and when it does, the CPU at its maximum frequency is supposed to call for a particular VID. The motherboard then adds/subtracts the voltage you set from this maximum VID it calls for and ONLY applies for the Turbo of the CPU, no other frequency/VID.
There is ANOTHER version of this, where you input your actual maximum Voltage that the motherboard is supposed to supply when the CPU goes into Turbo. But this didn't seem like it made its way into the generation of motherboards that you and I are using.
Not only this, but because of an update since Windows 8, this recognition that the CPU is going Turbo is not working properly. So in some things, it tells the motherboard to throw the extra voltage on, and in some other things, it doesn't. Even when both use the CPU to the max. So... Yeah. It's a messy section of overclocking.
