Slim EATX case, should I ditch my 5960x or the battle of centimetres

[Tuscany]

Greeting great community!

I have been busting my head for the past days and although my question is not really small, I decided to give it a shot.

Currently I use the big old, but still my favorite, CM Cosmos S to accommodate my ASUS R5E, 5960x, 290X + the rest and custom loop. Great build for me, nice water cooling but for a very trivial reason I will need to let it go - I have now less space for my PC so I need to shrink it. Obviously this is big, power hungry task. No matter what I do, my new case should not be more than 21cm in width. And obviously it will need to have ATX PSU compatibility, as I don't think SFX PSU will see bright days with these overclocked.
The only suitable case I found was Phanteks P400.
And the Cerebrus X, obviously. The only thing that bothers me is the ATX PSU placement. As if it makes it even harder to do the things, which are hard enough with these parts.

Are there any other slim, E-ATX, ATX PSU cases out there which I missed? It has to be max 21cm. Even 23cm is already breaking the deal.

Or should I ditch all of this now and either go with current gen mATX/ITX hardware or wait for the Ryzen 4000 family and generally move down to smaller farm factor?

 

[GuilleAcoustic]

I won't answer the question, sorry ... but what's your wattage requirements ? Silverstone offers 700W SFX with 80PLUS Platinum rating and 800W SFX-L with 80PLUS Titanium rating

SX700-PT

After pioneering full featured, high performance SFX power supplies in 2012, SilverStone has continued refining the segment it has created. The SX700-PT is yet another evolutionary step toward perfecting this small form factor power supply category. It is more powerful without growing in size to...

www.silverstonetek.com

SX800-LTI

Since its launch in 2015, the SFX-L form factor has garnered popular recognition and support among enthusiasts with its larger 120mm fan able to achieve better balance of power and quietness in small form factor PCs than what was possible with standard SFX. And as a leader in power supply...

www.silverstonetek.com

 

[Tuscany]

Completely honestly - I don't know that. I never measured the system and I cannot measure it at the moment - broken pump :/

However, by reading on the internet I'd calculate something like this for peak consumption:
290x - 300W
5960x OC - 300W
HDD&SSD - ~50W
Fans - 20W
Other - maybe another 30-40W


So, this totals up to ~700W. Of course, it could be less in reality and this will be only while gaming or so. But nevertheless, fully loaded SFX does not sound like a great deal :/