Unusual Power Consumption

Find Intense PC news at https://plus.google.com/+Fitpc-by-compulab/
Post Reply
IntensePC_User
Posts: 47
Joined: Mon Feb 25, 2013 11:32 pm

Unusual Power Consumption

Post by IntensePC_User »

I have an Intense PC Pro running Windows 7 with no display or peripherals attached.

Idle power consumption, with no USB devices attached, is around 11 Watts. This is great.

Idle power consumption, with a USB device attached, is 23 Watts. This additional 12 Watt power consumption is regardless of the type of USB device used and much higher than the USB device's actual power consumption. This means that at full CPU usage the power consumption is over 30 Watts, which is above the stated power consumption in the tech specs of 26 Watts.

Does anyone have any ideas as to why this happens and how to fix it?

Thanks!

gabrielh
Site Admin
Posts: 1260
Joined: Thu Jun 02, 2011 1:13 pm

Re: Unusual Power Consumption

Post by gabrielh »

Indeed, that is abnormal behavior.

Which OS do you use?
Reboot your PC and enter in to the BIOS menu. Please check in this mode power consumption with and w/o USB device attached.
Gabriel Heifets

Fit-PC2/3/IntensePC support.

IntensePC_User
Posts: 47
Joined: Mon Feb 25, 2013 11:32 pm

Re: Unusual Power Consumption

Post by IntensePC_User »

I'm using Windows 7 Pro, 32-bit.

It seems that the lowest power consumption occurs only in Windows with no USB devices attached AND no display attached. That is to say that: Attaching a display OR USB device OR both makes the power consumption jump from 11W to 23W.

It also seems that low power USB devices (like a keyboard) don't cause this to occur. High power devices (like a HDD or Data Acquisition Board) do cause this higher power consumption to occur.

OK, so now for the requested results:
In the BIOS with USB keyboard and display attached - 25W
In the BIOS with only USB keyboard attached - 25W
In the BIOS with only high power USB device attached - 25W
In the BIOS with only display attached - 25W
In the BIOS with nothing attached - 25W

IntensePC_User
Posts: 47
Joined: Mon Feb 25, 2013 11:32 pm

Re: Unusual Power Consumption

Post by IntensePC_User »

I've got an update.

I've been measuring the 120VAC power consumption, before the power supply, using a Ryobi Power Usage meter. I decided to verify this meter is giving me correct results...

Unfortunately I don't have a multimeter that can measure AC current, but I do have one that can measure DC current. So, measuring DC current directly into the Intense PC Pro I get much more reassuring numbers. At idle, with nothing connected I calculate about 10 Watts. At idle with all of my high current USB devices connected I calculate about 13 Watts, which corresponds directly to the devices' expected power usage!

To be sure, I also measured in the BIOS like you suggested. I calculate 15 Watts with devices connected and 14.5 Watts with nothing connected.

It seems that the fancy Ryobi power usage meter may be doing some hidden auto ranging and the jump may be due to that.

So, I'm happy to report all appears well and have learned not to trust the Ryobi meter!

Post Reply

Return to “General Intense PC questions”