I've flicked through the GAF thread and from the responses it seems this person is trusted:

Originally Posted by M3d10n

The Pro actually has a certain new GPU feature specific for VR that can help a good deal with performance beyond just being able to render twice as many pixels, but seems it hasn't "leaked" anywhere unlike the checkerboard stuff because I haven't seen anyone talking about it in the media.

Originally Posted by M3d10n

It's in the dev docs, with steps showing how to use it and everything. I guess we'll hear about it when some devs start using it and want to show off, since it's not a free lunch and takes some work to use properly.

Sony is funny that way. A few system updates back they added the PS2 emulator to the PS4 OS and never told anyone. People found out when Star Wars Battlefront came with free PS2 games.
PSVR will be the main reason I upgrade to PS4 Pro. I was hoping the extra break out box wouldn't be needed on the Pro but I haven't seen any info confirming it. The extra GPU feature sounds good though.

I'm personally not interested in VR gaming, but that feature for the PS4 Pro sounds interesting.

Just like GAF said the pro will have 5.5TF.

The role reversal keeps going this gen, ps4 secret sauce!

More of dat Secret Sauce.

secret hidden power ki.

That's fucking awesome. I love a bit of secret sauce!

And ps4 pro will be the ultimate platform for VR gaming too.  Very hyped about this. 

I's well known that the PSVR will be powered from the cloud.

Is this the death laser he's going on about? I thought that was still under NDA... 8-P