http://anandtech.com/weblog/showpost.aspx?i=482

Very high efficiency stuff coming soon.

The lowest spec version is an 850w box? Why? Anyone who needs that much power doesnt give a shit about efficiency.
Give us a 85%+ 400w unit and that'll be better.

With that many vent holes it will be pumping 20-25% of the warm air, straight back into the case.

Although with my scythe kama bay fan that will actually help keep it nice and cool.

Because there are some gamers out there that want to play hi res with multiple monitors without listening to a leaf blower PSU fan.

But I agree. I'll not be buying anything that high a wattage.

Why? I don't get the point.

If a PSU with a high maximum power has better efficiency than a unit with a lower maximum power, why not to get the former?

It's not like the higher maximum power is somehow bad in itself.

Hypothetical question: Would you buy a min. 95% efficient, 5 KW PSU, if it was affordable?

Ok, there's one very sensible reason: Units with high maximum power tend to be expensive.

I would not buy a PSU that is either too inefficient or too expensive. Basically I'm always trying to get the maximum efficiency for my load range in my budget (assuming construction quality etc is equal).

I would buy a 50 million billion watt PSU if it was efficient in my computer. But i would not want to pay a lot for capacity i will never need. I paid 67€ for my Pro82+ 425W, but i would not pay 140€ for the 625W version since i dont need it. So if the 625W version was the "smallest" one, i would buy another brand of PSU for less. Or something in that direction. [/code]

Let me show you some real world efficiency numbers:




So if my PC idles at 65 watts DC 99% of the time which PSU in that table saves me the most money in the long run?

The Corsair VX450W and Seasonic S12-380 are about equal at that load level at around 79% efficiency.

Notice that the 700 watt Seasonic and the 620 watt Corsair are both around 70 to 72% efficient at that load level.

So if I know for a fact that my PC idles that low or lower I'm better off with the lower wattage power supply.

It's a simple matter of reality. Each power supply will have a different efficiency at different wattages.

Now lets add some higher efficiency numbers and ignore the 40 watt level



The 82+ Enermax outshines the lower wattage units all the way across the board. Impressive, but this is an apples to oranges comparison. We are now comparing a new product to products that are several years old in design.

If we had real world readings for the 82+ enermax 385W or 425W I would expect that they would show better efficiencies at low wattages than the 625W model does. Given time we will get real world numbers from lower wattage 82+ units.

My point isn't that 85% efficient 850W units are bad. My point is that a properly designed 450W unit would serve my needs better and at a lower cost and a lower price.

That's a very fine reply, thanks. But maybe instead of just saying that you'd never buy such high power PSU, you should say "It'll probably be too expensive and have worse efficiency on lower loads"

I'd still like to see a review of one of these models to find out for sure how efficient they are at lower loads. I don't draw more than 100W at idle myself either, and that's the load that I want to optimize.

I don't get it, still no PSU?

Anyway that fan is 1600 RPM and is going to be louder than necessary. I would've settled for a 1200 RPM fan. You could probably do the 7V mod on it though (or use a fan controller) so that's fine I guess.

bit-tech takes a first look at the Revolution 85+ 1050W unit.

http://www.bit-tech.net/hardware/2008/0 ... n-85-psu/1

So what do you get with higher efficiency at lower wattage use, lesser power bills??

Thats to force you to buyer higher wattage units in turn giving them better profits since there is no other choice, if i were a PSU manufacturer i wont be the first one to offer 85% on low wattage.

I'd assumed that the reason some people buy higher rated power supplies is that the fan doesn't really kick in until it reaches a load of 50% - 60%; therefore when the PC is working at max, say using 300W it will still be pretty quiet.
That would be my reasoning anyway.

Also, given that a 5% difference in efficiency at idle load of 60W is only 3W, leaving a PC on idle for 20 hours is equivalent to having a 60W light bulb on for 1 hour - pretty inconsequential in the scheme of things really.
(Particularly if you have a wife like mine who insists on leaving lights burning all round the house to make it "look cosy" even if nobody is using the room all evening. )

Does anyone have any real-world experience with the Revs?

I happen to be one of those people with a thirsty rig who also likes silence. I also have a defective PSU at this time, so I'm going to be replacing it.

The reason I would buy a Rev at all (only the 850W, the rest are above my power envelope) is that at load my rig can break 65% of capacity on a Modu82. I'm running a Q6600, a 780i and two GTX260s, with a couple hard drives for good measure.

I'd get the 850 to be assured of never spinning the fan up. The 900W I have right now has never spun up, but that might also be because it only pushes 11.25 on the 12V rail. Hell, the fan doesn't even spin on boot.

Judge has the right tack. Most of the users here wouldn't come close to breaking 50% on a 500W even, but there are some of us who can pull 400W at load. Just look at Kate's rig in the Gallery as an example of a rig that will spin up a 625W unit.

The quietest PSU ever made is no longer quiet at 100% load. That's just simple logic. So for me, I want to over-buy on the PSU to keep the fan at idle when my box is at load.

I'm looking between the SeaSonic M12D-750W and the Rev 850, but the M12D is off-market right now for QA revisions, so most likely I'll end up getting the Rev.

Review @ Xbitlabs:

http://www.xbitlabs.com/articles/cooler ... html#sect0

Unfortunately no dB measures and their 'quiet' claims are somewhat dubious.

I've had an Enermax Revolution 85+ 850W for a few months now, and since the beginning, the fan on it has been very quiet, except for one flaw - it was unbalanced like described in the Bit Tech review for the 950W model. (started out sounding like an occasional thump inside the psu, but that soon worked out to crickets at about 5 chirps/sec.)

so after living with it for a couple of months, I replaced the fan with a Scythe gentle typhoon (1450rpm)- it's very quiet now.

btw, the vent holes on the inside of the case side of the PSU has a PCB card w/ those 8- and 12- pin outputs between it and the fan, so most of the air would be pushed to the exit side of the PSU.

and I replaced the 135mm fan w/ a 120mm. The red trim around the fan is actually a separate metal piece, which I used to clamp down the wires (taken from the old fan's RPM header wires) that are suspending my new fan in the hole where the larger fan was. I used a bunch of electrical tape to seal the gaps and create a downward opening lip. (it looks pretty decent [my case is closed and windowless anyway] and works great - I wouldn't go back to that chattering fan)

Summary: While I was disappointed w/ the chattering unbalanced fan, the PSU is very solid and I'm confident in it's efficiency, because it produces little heat compared to my 4 y.o. PC Power & Cooling (1KW-SR rated 80 Plus - from before I learned that it was higher amps, not wattage, that my graphics card needed). And I love how the Enermax keeps the fan running for about 45 seconds after shutdown or sleep - that was one feature why I bought it. We've been having a heat wave for the last week here in So Cal (30C indoors), and the PSU would vent warm air (feels like 98-110F, just a guess) and after shutdown/sleep, the fan continues cooling until it's just warm. Within another minute or so, you don't feel any residual heat coming out the top (have fan side up), as it's near room temp already.

Here's a link to pics of my setup, showing the PSU before fan-swap and after.

http://www.flickr.com/photos/mlcca/

Update: I ended up putting the original fan back into the PSU. as the ball bearings started getting audible (when things are very quiet, you can hear that high-pitched whine).

My PSU may have been dropped during shipping and that caused the imbalance, I don't know. But it seems to me like it's a luck-of-the-draw situation, where some people get quieter units than others.

I tried running the Revolution without the fan, but after a few days, and w/ warmer weather, a burning smell could be detected. So I guess I'll live w/ the original fan until I get a Nightjar fanless PSU, Seasonic X-650, or whatever else comes out.