Aurora R6, Memory stuck at 2133mhz and missing options in Bios

Try releasing the fleas: Flea power 

If that does nothing, try the coin cell battery removal/reinstallation procedure. This will reset all BIOS saved settings back to default. Coin Cell 

If none of that works, put the original OEM memory back in. These systems are limited in aftermarket support and the only memory modules to guarantee to work are the OEM modules.

Thank you both @Vanadiel  @ProfessorW00d for the answer. So if 2400/2667mhz is the max speed allowed, is there a way to increase the speed of the two sticks I bought to one of these values at least instead of their stock one? There is still the problem of having no options showing off at all under performance tab of the bios

And what the professor said.

You can download CPU-Z, and look under the SPD tab to see the embedded XMP profiles on the memory sticks.

Chances are 2667 Mhz is not listed under the profiles.

CPU-Z 

I tried releasing the flea but no change in any way. I'm not sure about the coin cell one since there was already an option in bios to reset to default (which I enabled, but there was still no options at all under Performance in bios). Is it safe to remove and reinstall the coin cell? Sorry if this sounds dumb I'm just not much knowledgeable about this.

The professors answer is the correct one: your system supports up to XMP 2667 Mhz.

You installed Corsair Vengeance LPX 3000mhz, and 3000 Mhz is not a supported XMP profile on your system.

It would show up as long as the memory is supported. Officially the only 100% supported memory is the OEM memory.

XMP profiles are embedded on the memory sticks and are not part of the motherboard data. They are strictly part of the memory modules and proper support is required by the motherboard for them.

Thanks for the help and explanation, much appreciated. According to the R6 manual and to Professor's screenshot, Kingston memory kits up to said 2666mhz speed would be compatible as well, in any case I'll give it a try and hope XMP will properly show up. Also, would there be any explanation as to why there are no other options available apart from XMP in performances tab of bios and why the Overclock feature is greyed out? 

Looks like there is a single XMP profile with a frequency of "1499mhz" according to CPU-Z so I'm guessing this is a no. So assuming I'd have 2666 mhz sticks installed, would the XMP option show off in bios? Or is the problem of having no options visible is not related to this at all?

It's typical whenever I does not like the memory modules, to disable all overclocking in the BIOS.

It's one of the negatives of OEM systems like this.

So I removed both sticks and replaced them with the original one that was shipped with the Aurora R6 to see if this was the culprit but it still displays "Overclocking feature [disabled]" with no option available, so the problem doesn't seem to be related to memory modules. I also tried to reset the BIOS options, but it remains the same. Is there any other explanation as to why this would be disabled and greyed out? 

We don't know anything about the OEM memory that came with your Aurora R6. It may be like this Kingston Aurora R6 memory which has an SPD speed of 2666 MHz and no XMP profile.

You can check the OEM memory with CPU-Z to see what the profiles are.