t-break posted a new article today titled "Breaking the 20k Mark in 3DMark
Vantage".

After hours of tuning to see what the optimum voltage setting would be with best clock speed so I don't throttle the GPU and bring down the scores, I managed to stick with 1.5v on the GPU running at 1050MHz and 1200MHz on memory. I managed to obtain a total score of 17342 Mark, comprising of 19393 GPU Score and 13165 CPU score, so that's an extra 1587 points achieved by simply overclocking the GPU's.

Breaking the 20k Mark in 3DMark Vantage