The bound exists, but it's so many orders of magnitude out that for all practical purposes we don't need to worry about it.

Of course, however, heat dissipation presents similar challenges.

It'll be interesting to see how/if quantum effects will be used in future computing tech (well aside from the whole quantum bangaps in semi-conductors). Effects like thermal super-conductors could enable much higher heat in a given area, perhaps built with quantum dots on semiconductors (IIRC, I thought some researchers tried that).