Which of these three PSU's would be a decent upgrade?

[Smiffy-UK]

Hey, I currently have a BitFenix Formula Series 550W 80 Plus Gold Power Supply, been using it since Jan purchased from here it's been pretty good so far,

Looking to upgrade within next week, which of these three would you choose, I will be upgrading to rdna2/ampere and also zen3 (10c/20t if true)

I've narrowed down my search to these three.

BitFenix Whisper M Series 850W 80 Plus Gold Modular Power Supply (£114.95 Warranty: 7yr)
https://www.overclockers.co.uk/bitf...plus-gold-modular-power-supply-ca-22d-bx.html

Super Flower Leadex III 850W 80 PLUS Gold Modular Power Supply (£119.99 Warranty: 7yr)
https://www.overclockers.co.uk/supe...old-modular-power-supply-black-ca-062-sf.html

Phanteks Revolt Pro 850W 80 Plus Gold Modular Power Combo Supply (124.99 Warranty: 12 yr)
https://www.overclockers.co.uk/phan...old-modular-power-combo-supply-ca-08a-pt.html

 

[Smiffy-UK]

I would go for the Phanteks out of those three followed by the Superflower. I wouldn't go with the Bitfenix due to the big shroud over the 24 pin connector making it stick out much more than it normally would. It's a good psu but that shroud put's me off. Another option would be to wait until the Corsair's come into stock on the 22nd and go with a RM or RM-x.

Thank you for your suggestions.

What makes the RM and RMx worth the wait and what's the difference between the two models?

I can wait so I'll probably get one of them jot not sure on the RM or RMx