GTX 970 VRAM allocation bug
Oh sounds very bad

in German with many details

Looks like nvidi dont test their hadware... Wink
It doesn't sound bad at all, and it's certainly not a matter of Nvidia not testing their hardware. It's a matter of using a lower-performing memory controller on a non-flagship GPU, which is entirely what one should expect.

This likely won't have any impact on compute performance unless you're loading up a hash list with hundreds of millions of hashes. And even then, the performance hit is likely far less than the performance hit all AMD cards take with that many hashes, because if you haven't noticed, the memory controllers on even AMD's flagship GPUs are really really shitty.

EDIT: Good explanation for why this isn't a bug but rather by design can be found here:
This 'feature' had already been on earlier cards.