Model 25 Power Use

Ever wondered how much electricity an average Model 25 uses? This page includes samplings from a few different Model 25s with different configurations and processors. To be added are results from testing EduQuest machines and more Model 25s in more configurations.

The good news is that the Model 25 uses much less power than IBM's printed ratings suggest. The Model 25 appears to be a pretty economical computer to operate.

Model 25 with Reply Board

Intel 80486DX4-100MHz CPU
1.44MB Floppy
600MB Seagate Hard Disk
2 Option Cards -- Accton ISA Ethernet NIC and a Creative Soundblaster with 2W onboard amplifier

At power on and in DOS, power consumption is as follows:
82~87 Watts
.93 Amps
.77 Power Factor

Fully Booted In Windows 95:
92 Watts
.99 Amps
120 VA
.77 Power Factor

Model 25 XT with Monochrome Display

640K RAM, 720K Floppy, 20MB IBM Hard Disk

61 Watts
.76 Amps
95 VA
.64 Power Factor

With this machine powered up--from boot time until it was ready to use at a DOS prompt and even after I loaded a program that uses the screen at the highest possible resolution (640x480 at 2 colors) the power usage figures remained the same.
Interestingly enough, IBM's own printed power use figures on the back of the Model 25 are nowhere near what I measured. I would guess that IBM's figures are worst case...but I would think the Reply-board equipped machine above would meet or be much closer to the worst case figures.

Just in case you don't have IBM's figures from the back of your Model 25, here they are:

2.8 Amps
200 Watts

1.7 Amps
200 Watts

I lack the resources to test power consumption at 200-240 volts, so the best thing I can recommend is to cut my readings in half or to make your own measurements on your Model 25.

More machines power figures will be coming as I get the chance to plug them into my in-line meter.

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