Initial power draw picoPSU concern
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Author:  Richard [ Tue Jan 07, 2014 2:06 pm ]
Post subject:  Initial power draw picoPSU concern

I have read countless forums (including this one!) and reviews looking for a psu for my mini-itx build for about two days now.
I have settled for all power hungry hardware(still have psu, SSD and case to decide). My problem is that I am not sure about initial power demand.
I think I am pretty close to what the rig will draw. It will be somewhere along those numbers.

Asus H87I-Plus (30 W)
I3 4330 (54 W) + box fan (? W)
4 WD RED 3 TB (16.5 W)
SSD (3 W)
2x4GB G.Skil F3-12800CL9D-8GBRL (4 W)
Case fan (? W)

This adds up to around 120 watts.
I could be wrong here, though. Most of the wattage is my estimations, based on many different forums.
So my question to you is if you think either a picoPSU (150 or 160) or maybe even electrodacus's 130W PSU would be enough to take me trough the start up peak? If I got the numbers right, which I hope you can correct if they are off. I have used a number of different PSU calculators, but they all seem to count way too high. Or I am doing it wrong...

This will run either win7, 8 or win server x, possibly WHS.

Also my final question will be about the number of drives I intend to connect, all in all 5 of them (6 is max on the board). I get that I have to use splitter cables to either of above mentioned PSU's. But how many drives can I add before I am using too much power on one cable?

Any help will be greatly appreciated!

Thanks in advance!

Author:  xan_user [ Tue Jan 07, 2014 4:27 pm ]
Post subject:  Re: Initial power draw picoPSU concern

I thought youd be ok, even before I saw this...
Uses an installed fast SSD (min18.6GB available capacity required) as a cache for frequently-accessed data. Key benefits include reduced load and wait times, and lower power consumption through the elimination of unnecessary hard drive spin. This technology combines SSD performance with hard drive capacity, operating up to 6X faster than a hard drive-only system.

Author:  Richard [ Tue Jan 07, 2014 4:50 pm ]
Post subject:  Re: Initial power draw picoPSU concern

Thanks for your time xan_user!
Unfortunately, at least as I see it, it doesn't have anything to do with the start up procedure and initial power peak. It cuts some time during operations.


Author:  HFat [ Tue Jan 07, 2014 7:26 pm ]
Post subject:  Re: Initial power draw picoPSU concern

Your numbers are off.
The drives will probably draw at least twice that when spinning up.
On the other hand, there's no way the CPU will draw close to 50W and I doubt the board will draw that much either.
So if you simply add the watts, it looks like you ought to be OK. I haven't looked at the details.

I wouldn't use a pico for a 4-5 drives server anyway. Some regular PSUs have decent efficiency and if efficiency was so important, you wouldn't be using this sort of gear anyway.
Depending on your application, consider using basic server gear. Considering how much these drives cost, you should be able to afford it.

Author:  thierry. [ Tue Jan 07, 2014 10:35 pm ]
Post subject:  Re: Initial power draw picoPSU concern

The first time I measured the real consumption of my computer, I was surprised. And I realized how hard it can be to estimate, just form the components.

On my previous build, I had B75M (mATX) with i3-3225, 1 SSD, 2HDDs, 2x 4GB RAM, 180mm front fan at 700rpm.

Although my i3 TDP was also 54W, I was drawing 44W at idle and 64W at full load, with 2 drives spinning, encoding on the SSD, etc. (measured with a kill-a-watt, 220V AC here)

Author:  HFat [ Wed Jan 08, 2014 12:14 am ]
Post subject:  Re: Initial power draw picoPSU concern

Intel's TDP values are marketing-driven and can not generally be used to determine how much a particular CPU model will consume.

In many cases, you need to stress the CPU's integrated graphics to get it to consume as much as it can. Some types of loads can also cause more power consumption than others.

Author:  Vicotnik [ Wed Jan 08, 2014 3:21 am ]
Post subject:  Re: Initial power draw picoPSU concern

In my experience five 3.5" HDDs will spin up, but not six. This is with a picoPSU and a good 60W brick. Four WD Reds is what I use now and it works fine. But it's something I run this way for fun. For long time stability I would recommend a normal ATX PSU for a system like this. The efficiency of a modern unit like the Seasonic G-360 is not bad and the amount of power saved with a low power picoPSU system is less than it used to be.

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