I think something is wrong with TPU's bench system.

They are the only people who have this "problem".

Also, linkboost support is now gone since 590sli.

Also, since when did linkboost increase the card clocks?

Linkboost never increased the card clocks, only the pci-e and chipset buses.

Also, since when is the core clock dependent on pci-e bus?

I don't think TPU knows much,. and they are just spreading misinformation.