I've just been "testing" a PC based around i7-2600K and GTX560 Ti. With the CPU over clocked to 4.7GHz for good measure.
I've got my best "testing" PSU running it, a mighty Seasonic S12II 330! Runs it fine too! OK it's 10% over 300w but with some SMP and GPU folding I'm seeing 330w from the wall. Efficiency guess around 84% (from SPCR 380w review on 240v AC) so this is 275-280w DC load!
Regards, Seb

That's pretty cool. Nice that this thread is still going, after all these years!

Here's my rig: (ok it's not 300W PSU but still under 400W)

Antec NSK 4480 case (with BasicPower 380W PSU or whatever it's called) - mind you this case is at least 5 years old
Intel Core i5-2500K (stock cooler ATM)
ASRock Z68 Pro3-M motherboard
Gigabyte Radeon HD4850 GPU
Creative X-Fi Xtreme Music
1x 120mm case fan (Antec TriCool, set on medium)
1x 80mm case fan (Arctic P80L, set by PWM at 50%)
2x Western Digital Caviar SE 160 GB SATA HDDs
Various USB devices (mouse/keyboard combo, webcam, the occasional external HDD)

I've never heard the PSU fan power up, and even in extreme conditions the air that blows out is mildly warm (I'd say below 40 degees)

I find it funny because I've wanted to switch with a Sirtec HighPower 410W PSU (review: http://www.techpowerup.com/reviews/Sirtec/ATX-410-212/)but the combined 12V maximum wattage was only 240W, although it stated that the maximum current was 15+18 A, which should have resulted in 396W. I stuck with my old Antec and never looked back

330W from the wall :
X-650
Asus P5Q-E
Intel Q9550@3.4GHz
2xGigabyte GTS450 OC (@900/1900/3800)|
Corsair 2x2Go XMS2 DHX cas 4 @4-4-4-12
Intel X25M G2 160Gb
Samsung 1TB in SQD
and 2 Nexus 120mm fans.

A bit of an old setup for now, but it still folds like a champ

Nice setup! Hardly "old", imo. The average PC user would not be able to discern any difference between your rig and a "current" sandy bridge rig with >90% of tasks.

Will a 300w SFX PSU (Seasonic SS-300SFD) power my future mini pc?
-Intel 2500k (probably Ivy Bridge, if not, the current Sandy Bridge rev) -> stock or with a little oc (not sure if i'll need it, prob not)
-Z77 mini itx board (or any z68 or H67 mini itx board)
-8 GB ram
-1x SSD + 1x 2.5" hdd 5400 rpm
-nvidia 560 TI (stock, nothing oc)


My current pc (560 ti + 4 GB ram + 1x 3.5" hdd 7200 rpm + intel E6400, all default speeds) managed to draw about ~295W from the outlet (Antec NeoHE 430W psu), in one particular game. The E6400 cpu has a 65W TDP, but the Sandy Bridge version of the 2500K cpu has 95W TDP (!!!), so what do you think? Even the upcoming Ivy Bridge CPU has a rated TDP of 77W, higher than my current cpu. Will this PSU be enough or safe to use? Or should i look at the higher rated Silverstone SFX psu (450w)? The only thing that keeps me from getting the Silverstone is that i think it will be much noisier, given the smaller fan (only 15mm high) and poorer fan controller (i assume).

Also, can the fan in the Seasonic be swapped with a 92mm one? I can cut the psu case, make another one, no problem, what i don't know is if it will be the same height (76.5mm) as with the 80mm fan. Height is important because of very limited space in my mini itx case.

Anyone, please? I need to make a sfx buying decision in the coming days.

imo, your system might be too close to the limits of the Seasonic for it to stay quiet. What is the case?

Custom made from scratch, the psu will draw fresh air from outside.

You are better off with an ATX PSU ~400W. Since you're making your own case... why not a fanless X400?

A normal ATX is too big for my project, i want to build the smallest gaming mini itx possible. But i'll think about it.

I'll see if i could replace the 80mm x 15mm fan in the silverstone with a 92mm x 25mm fan. It will add 10mm to the height of the sfx, but i don't know if the other half of the fan will fit inside the psu (basically, instead of 80mm x 80mm, now it will be 92mm x 92mm).