Nvidia's Founders Edition RTX 2080 and 2080 Ti graphics cards might be more expensive and higher clocked than the standard versions, but they may not be the best versions of the new GPUs. Nvidia is reportedly binning the GPUs and boards for both cards, meaning that the best ones will actually go to its partners who will add their own aftermarket coolers and factory overclocks.
Binning is a process by which chips are tested to see how capable they are at different clocks and voltages. Even if they are designed and printed the exact same way, differences in their physical make up at the microscopic level can lead to drastically different performance capabilities. That's why some CPUs can be overclocked further than others and it's why Nvidia is binning its new GPUs.
But of course, it does charge for that privilege. That means that third-party manufacturers who want to make their own overclocked cards will need to shell out a bit more for them. Taking things a step further, Nvidia has also reportedly banned overclocking on cards that aren't especially binned for the process, according to TechPowerUp. That means partner companies can't roll the dice and see what they can push out of non-binned cards.
That said, there's nothing stopping the overclocking entirely. That means that if you buy a stock clocked RTX 2080 or 2080 Ti, you might be able to push it to relatively high clock speeds yourself. It just won't be as capable as some of the binned GPUs with factory overclocks.