psu advice

decimusbell

Chassis Packer
Original poster
Oct 4, 2018
14
2
HI all i have a metallic gear mini itx case. http://metallicgear.com/products/Neo-Series-mITX

it will fit a full size psu but I'm undecided whether to go with full size or sfx psu-

my options are the corsair RMX 550- https://www.corsair.com/uk/en/Power/RMx-Series/p/CP-9020177-UK
or the corsair sf450- https://www.corsair.com/uk/en/Categ...pply-Units-Advanced/SF-Series/p/CP-9020181-UK

both are good, fully modular, have 0 rpm mode. the 550 is gold and the sf450 is platinum.

given the choice, what would you go with and why?
my only thought about it is that if i ever change the case the likelihood is that i will go smaller.
also ive done a little psu calculation and i only need 300-350 .
 

Aux

Cable-Tie Ninja
Dec 5, 2018
179
155
SPEC
  • CPU - Intel - Core i5-8600 3.1GHz 6-Core Processor
  • CPU Cooler - Cryorig C7 CU

  • Motherboard - Asus - ROG Strix Z370-I Gaming Mini ITX LGA1151 Motherboard

  • Memory - Corsair - Vengeance LPX 16GB (2 x 8GB) DDR4-3200 Memory

  • Storage - Samsung - 970 Evo 500GB M.2-2280 Solid State Drive

  • PSU - Corsair - SF 450W 80+ Gold Certified Fully-Modular SFX Power Supply

  • Case Fans - 3x Noctua NF-A9x14 PWM Slim 92mm

this is your spec from other posts, which gives 100W, so I presume you have added a graphics card.

as you say your psu calc said 300 to 350 W

With your current calc I would take the sfx 450W. Calculated power 350W plus 100W for overheads/relaxation over time. Platinum for better quality components. Only £10 in it between the two power supplies. And the SFX protects you if you want to stay small form factor.
You will probably need an SFX adaptor plate for the case, looks like it was designed for ATX power supplies
 

decimusbell

Chassis Packer
Original poster
Oct 4, 2018
14
2
this is your spec from other posts, which gives 100W, so I presume you have added a graphics card.

as you say your psu calc said 300 to 350 W

With your current calc I would take the sfx 450W. Calculated power 350W plus 100W for overheads/relaxation over time. Platinum for better quality components. Only £10 in it between the two power supplies. And the SFX protects you if you want to stay small form factor.
You will probably need an SFX adaptor plate for the case, looks like it was designed for ATX power supplies

well done - yes same config although ive gone for corsair 240mm aio. and added zotac graphics card. the sf450 comes with plate for case. which is great. thanks for you advice.
 

Smanci

SFF Lingo Aficionado
Apr 21, 2017
126
160
There's essentially no difference in efficiency and electrical quality but RM550X (2018) is going to run a lot quieter, probably cooler, under any scenario. SFX makes little sense in such a big case but if you do plan to dowsize...
 

decimusbell

Chassis Packer
Original poster
Oct 4, 2018
14
2
There's essentially no difference in efficiency and electrical quality but RM550X (2018) is going to run a lot quieter, probably cooler, under any scenario. SFX makes little sense in such a big case but if you do plan to dowsize...

the heat and noise worries me now- i want my machine to run very quiet and cool
also i want my psu to run on 0rpm mode for as long as possible
 

Aux

Cable-Tie Ninja
Dec 5, 2018
179
155
the ATX 550 will run cooler and quieter with its larger size for sure.

At the end of the day its your call
 

Smanci

SFF Lingo Aficionado
Apr 21, 2017
126
160
well done - yes same config although ive gone for corsair 240mm aio. and added zotac graphics card. the sf450 comes with plate for case. which is great. thanks for you advice.

For SFF where PSU acts as exhaust fan, fan profile is more important than 0RPM mode. The fan will turn on quicker than normally and temperature control ramps it up more aggressively.

If we go by Tom's tests, SF450 Plat fan kicks in after 200W at ~1400RPM and RM550X near 300W at ~580RPM. 135mm fan spinning at 580RPM (till 450W) is practically the same as having it turned off but still indefinitely better than 0RPM as it cools the unit and keeps the fan from constantly ramping up/down.

It's a no brainer if you're sure you don't need the SFX form factor now or in near future.
 

Aux

Cable-Tie Ninja
Dec 5, 2018
179
155
you dont say what your gpu is.
It may be that your aio and graphics card will drown any noise from your chosen psu