Sorry but another small correciton needs to be done here.

The space of an HDD is calculated by using a Standard Base 10 system so that every KilobByte is calculated as 1000 Bytes, whereas a logial KilboByte is calculated using a base 2 system and is actualy 1024Bytes.

So as you go up each factor the disparity is larger and larger. For exmaple a 1 TB drive actually nets you 931 GB instead of 1024 GB which is a real Terabyte.

I hope the PS4 Pro also supports 2,5''-HDDs with 15 mm height instead of 9 mm... that would allow 4TB-HDDs

External HDD is USB3? Can you run games from the external HDD?

It really doesn't halve load times.
It is limited by the Mechanical Hard Disk Drives transfer rate, most will hover around 120MB/s these days, perhaps tank to 20MB/s during excessive random reads and writes.
I highly doubt a large % of console users even bother to upgrade their antiquated 5400rpm drives anyway.

This. Random Reads/Writes aka. Minimal latency in accessing data is the real strength of an SSD.

This is why SSD's  even if it has lower transfer rates than a Mechanical drive will always feel faster than a Mechanical drive.

Mechanical drives though will see no difference unless it's a a Burst transfer.

The right kind of drive pretty much excludes all mechanical drives.
A large portion of TLC NAND SSD's will probably not see much improvement either... Drives like the Samsung 750 EVO, 850 EVO, Intel 540, Crucial BX100 and others don't push Sata 2 very hard, let alone Sata 3, not in sustained transfer rates anyway.

When it comes to consoles, the few seconds you save on load times by going to an SSD is really not important in my opinion... You are better off getting the largest mechanical drive you can get so you can actually have a sizable amount of games installed.

Let's not forget that for Multiplayer games... Everyone will load at the same pace as the slowest player in most instances.

On the Xbox One you can. And it works amazingly well.

they are pretty much fixed

I meant internal SSD. The whole discussion had been about using an SSD thst has peak theoretical bandwith of 550MB/s over a SATA 3 interface. Of course we knkw there is a mechanical disk limitation. I referenced that in one of my earlier posts. 

Not all SSD's have peak rates of over 200MB/s. It's not just a mechanical disk limitation.

Great im waiting on the ps5

Ok, i don't know what this is about....

But let me be clear on what my point is;

With PS4pro using a SATA 3 interface, it means it has support for Drives that can take advantage of a 6Gb/s bandwidth. 

So as I have said, with the right hardware combination on the end users part (using a SATA 3 based SSD that has bandwidths up to 500MB/s+) you will no doubt get significant gains in specific use case scenarios (also like I have already pointed out earlier in this thread) when compared to the previous data 2 based interface setup. 

Unless you are trying to tell me that if I put in a 1TB Samsung evo drive into my PS4pro I will not get any meaningful benefit when it comes to load times (and I also pointed out exactly what kinda load times I was referring to) when compared to using a sata 2 based drive or even the same Samsung SSD over sata 2. 

The only other limitation will be on the cpu side or in a more crazy situation the devs coding their game in a way that such benefits can't be had. Now as for the CPU side, tons of random reads may be an issue, but that's not the kinda use case we are referring to here, I am talking about situations where a game has you staring at a loading screen for 30-60secs cause it's moving data from the hard drive. Now if that happens over a sata 2 interface with a 5400rpm drive with peak theoretical bandwidth of 150Mb/s (I keep using theoretical cause we both know that you don't always get the performance advertised on the box) going onto sata 3 with an SSD that has peak theoretical bandwidth of 550Mb/s ; will no doubt be doing better than the previous case scenario even when considering the same performance overheads. Unless the hardware (South bridge or cpu) just doesn't support such higher transfer rates. and there is no way we can know that till someone puts in a sata 3 SSD in the PS4pro.

I don't think Sony would have put in a sata 3 interface in the pro (while the PS4s still has sata 2) if there won't be any benefits. 

What correction is that? Or Correciton?

I pointed out that a 500GB drive will give 465GB, you work out that a 1TB drive will be 931GB, Double the stated amount in my post for a 500GB Drive, just wondering what aspect of my post you thought you were "Correciting"?