Minimum wattage PSU for Core i5 Haswell build

[dhazeghi]

I'm looking into downsizing my Haswell build to a smaller case, and as part of that, I was wondering with how small (wattage-wise) a PSU I could reasonably get away with. Yesterday I plugged in my newly-purchased Kill-A-Watt and at maximum load (8 threads of Prime95), I could get it to draw no more than 130W. Granted, I'm using integrated graphics (the machine is mostly for Lightroom, compilation and VMWare) but I was more than a little bit surprised at how low that number is. Most of the time it's in the 50-60W range.

Anyhow, my question is given these constraints, could I get away with something like a 150W PicoPSU? In addition to saving space, doing away with the PSU fan would be nice. Thanks.

Current system:
Core i5 4670K CPU (not OCed)
Gigabyte GA-Z87MX-D3H MB
Corsair CMPSU400CX 400W PSU
PCIe 802.11g WiFi
1 3.5" 7200RPM HDD
2 2.5" SSDs
3 x 4GB DDR3 memory sticks

 

[Flapdrol1337]

according to http://www.silentpcreview.com/article1008-page5.html your psu is a little over 80% efficient at 130W from the wall. So the psu only has to deliver about 110W. I reckon a 150W picopsu should be fine.

 

[fuzzymath10]

You'll be fine. I've squeezed an i7 3770 with an SSD into a 120W wide-voltage PicoPSU that has only 72W (6A) on the 12V. It can even go past stock turbos occasionally on my Z77 board.

 

[Compman55]

Being you will never max the CPU cores to 100% very often in real world uses, it should be fine. I think that if you plan to add a new GPU or mutiple GPU's later, plan accordingly. I bumped mine so I could add one top end GPU if I needed to.