For the GPU core, while Nvidia specs the nominal boost clock at 1710 MHz, in practice, the GPU boosts quite a bit higher. Depending on the game, we saw sustained boost clocks of at least 1830 MHz, and in some cases, clocks were as high as 1950 MHz. That's not that different from the Turing GPUs, or even Pascal. The real question is how far we were able to push clocks.
The answer: Not far. I started with a modest 50 MHz bump to clock speed, which seemed to go fine. Then I pushed it to 100 MHz and crashed. Through a bit of trial and error, I ended up at +75 MHz as the best stable speed I could hit. That's after increasing the voltage by 100 mV using EVGA Precision X1 and ramping up fan speeds to keep the GPU cool. The result was boost clocks in the 1950-2070 MHz range, typically settling right around the 2GHz mark.
Memory overclocking ended up being far more promising. I started with 250 MHz increments. 250, 500, 750, and even 1000 MHz went by without a problem before my test (Unigine Heaven) crashed at 1250 MHz. Stepping back to 1200 MHz, everything seemed okay. And then I ran some benchmarks.
Remember that bit about EDR we mentioned earlier? It works. 1200 MHz appeared stable, but performance was worse than at stock memory clocks. I started stepping down the memory overclock and eventually ended up at 750 MHz, yielding an effective speed of 20.5 Gbps. I was really hoping to sustain 21 Gbps, in honor of the 21st anniversary of the GeForce 256, but it was not meant to be. We'll include the RTX 3080 overclocked results in the ultra quality charts (we didn't bother testing the overclock at medium quality).
Combined, we ended up with stable performance using the +75 MHz core overclock and +750 MHz GDDR6X overclock. That's a relatively small 4% overclock on the GPU, and a slightly more significant 8% memory overclock, but neither one is going to make a huge difference in gaming performance. Overall performance at 4K ultra improved by about 6%.