450w Power Supply (low 12v ampere) for 7870xt i5-3350 combo possible?


I would like to use the following PSU (Coolermaster rs-450-acly)

Voltages                  3.3v      5v      12v1      12v2      -12v      +5vsb
Peak (60s)	           30A     35A      18A       16A         1A        2.5A
Continuity                 20A     25A     12A        10A         1A         2A
Max Power               191W            264W	         12W      10W
Total		                                    450w

It has 450watts in total at 80% efficiency and no PCI-E connector (would need to use 2 adapters). On 12v combined 22ampere/264 Watts and Peak 34 ampere/408 Watts. I suppose the "Peak" is the absolute limit before it shuts/burn down and for lifetime/stability purposes I also shouldn't run constantly on the "Continuity" Limits so I guess it is OK to count with 250w on 12v as Target?

It is supposed to run the following Components:

CPU: I5-3350 -> 70W
GPU: 7870xt -> 210w (undervolted about 180w)
RAM: 16GB Crucial Ballistix Tactical LP CL8-8-8-24, low profile (DDR3L-1600)
HDD: Toshiba DT01ACA Series 2000GB, SATA 6Gb/s -> 6W
SSD: Samsung SSD 840 Series 120GB, 2.5", SATA 6Gb/s
Case: Micro ATX Cube Aerocool m40 http://
DVD: 1-2 devices

So I got 250W(408W Peak) on 12v, The CPU,GPU and HDD will suck 300W in the worst case I guess. Obviously that's too much, if I undervolt the 7870xt as intended It will save me about 30 watts, so I'm at 270W, still to much, but not so far from the 264 promised watts. These watts I probably could gain by undervolting the CPU aswell. In the end, I believe it would stay usually below the 250W Target still very tight stuff.

I know, usually it would be recommended to use a stronger PSU, but actually I really want to use that one, possibly even go for a 660ti or standard 7800 if necessary but the above combination is my favourite by far.

Leaving me to the following Questions:

  • Do you believe, this PSU would be capable to run with the above components in the Aerocool m40 cube for several years without emergency shutdowns etc.?
  • As the PSU has no PCI-E connector, will two 2x4pin to 6pin adapters work without further problems? (I've seen 1x4pin to 6pin and 2x4pin to 6pin - whats the difference, recomendation for one of them?)
  • 2 answers Last reply
    More about 450w power supply low 12v ampere 7870xt 3350 combo
    1. I would look into an Antec , Corsair . or Seasonic 500 watt.

      Cosair CX500M > http://www.newegg.com/Product/Product.aspx?Item=N82E16817139050
    2. Well, thank you for your suggestion, though as told, I know it would be recommended to just use a stronger PSU but I'd like to use that one, so it would be nice to read some advice related to the questions I have asked.
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