Proof

For cntext:

SATA 2.0= 300MB/s peak transfer speed. We end up with around 150-240MB/s depending on type of drive used (5400rpm,7200rpm, SSD[limited])

SATA 3.0= 600MB/s peak. Real world performance is usually up to 500+MB/s depending on type of drive used (SSD)

Why this matters is cause this on the hardware side of things will amount to a literal halving+ in loading times. So anything that needs to be loaded from the internal HDD will happen much much much (and noticeably) faster. 

While this is a great step in the right direction (mind boggling the PS4 didn't launch with a 3.0 sata interface to begin with!!!) I would have been more excited about M.2 support with 2000MB/s+ speeds; ah well.... baby steps I guess. 

That's great, but apparently regular HDDs are typically much slower anyway and can't even reach the limit for SATA 2.0. Of course this should be great for SSD owners, but the chances are that you aren't going own an SSD large enough for a PS4. I bet owning an SSHD is the most common way to benefit from this.

I would never dream of buying a 500GB SSD for a current gen console. Way too small. The SSD part doesn't make that any better.

This should help as well:

http://gematsu.com/2016/10/ps4-pro-serial-ata-revision-3-0-support

Would an hybrid SSHD be any good ? I am considering getting one with PS4pro.

Just a minor correction to your comment here.  M.2 does not give you 2K+ MB/s speed by default. M.2 is just a small form factor connection for SSD's that was orignally designed to be used for ultra compact laptops and tablets. Even today most M.2 capable PC's still run use the SATA 3.0 bus for data transfers.

A PC needs to have the NVMe protocol and needs to have the SSD run along the PCIe 3.0 bus at at least 4X speeds to be able to acheive the the 2K+ MB/s speeds. There are 3 different conneciton types that can handle teh 4X PCIe speeds. This includes direct PCIe drives, Drives using the M.2 conneciton, Drives using the SATA Express conneciton, and finally the  SFF-8639 (now named U.2). In fact teh SFF-8639 (U.2) can actually exceed the max speed of both M.2 and SATA Express.

But in the end the key factor for speeds above 550MB/s is a combination of NVMe and using the PCIe 4X bus.

*Edit: There are also M.2 SSD's that don't support the NVMe protocol and thus cannot run over the PCIe bus and are limited to SATA 3.0's max bandwitth of around 550MB/s

Awesome, my 4TB Samsung EVO SSD will get fully utilized then. Pro is really turning out to be a really good upgrade.

A Hybrid SSHD would be practically useless on the PS4 as the technology only stores the most used files in the SSD part of the drive, which is usually only 8-32GB is size. The drive will likely only store OS files in the SSD portion which will not help you in games. Go full SSD or stick with an HDD>

Big deal, even the excisting hard drives will be a little bit faster but the win for hybrid drives and SSD's are insane.

I'll wait for 960GB SSD to hit the 100€ mark then. Thanks for the advice.