We use MSI Afterburner to overclock the graphics card. It was difficult to squeeze much more out of the Eagle, and we could only manage a +40MHz GPU offset, and a +750MHz memory offset, bringing speeds up to 20.5Gbps.
This wasn't much of an overclock at all, so it's not surprising to see the RTX 3080 Eagle only running 3-4% faster with the additional frequency. Once more, it does seem there is simply very little performance headroom left to tap into for Ampere, when it comes to overclocking.