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

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Last response: in Components
April 30, 2013 10:33:31 AM


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

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

  1. 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.?
  2. 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?)
  3. The operational Temperature is declared as 40°C which seems quite low too me, although in this test http:// it runs fine on nearly 50°C... Do you believe it will cause any Problem regarding the small aerocool cube case?

  • More about : 450w power supply low 12v ampere 7870xt 3350 combo

    May 1, 2013 10:30:47 AM

    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.