8088 cpu + monitor

[tipc]

What's the least amount of current draw from a typical 8088 cpu and color monitor @115vac? Let's say it's a 12-13" monitor.

[krebizfan]

Least amount should be zero aka "off."

Maximum power draw would be about 5w for 8088 and 12" color monitor could range up to about 50w. Don't plug big CRTs into the second connector on the computer's power supply.

[tipc]

By cpu I mean main system unit. Not the uP.

So will an ibm compatible + color monitor ever draw more then 3 amps?

[krebizfan]

It would be difficult to get a 486 or earlier system to use more power than that unless you have a giant CRT. The ST-4096 hard drive could use up to 50 watts; 486 uses less than 10 watts; chipset another 10 watts; a few watts IIRC for memory. I can't find a quick reference to the maximum power draw through ISA, EISA, or VLB slots but I would be surprised by a 486 era video card using more than 20 watts. Earlier equipment used less.

[lafos]

IBM PC/XT 5160 with AST SixPak+, MFM controller, IBM FH 10 MB HD, Tandon FH Floppy drive, IBM floppy controller, and IBM CGA card:

Initial power-up = 104 W
RAM test = 85 W
HD boot to MS-DOS = 92 W
Idle = 85 W
Scandisk surface test of HD = 85 W

I didn't have the IBM monitor connected; this was strictly the PC

[kgober]

If you consider that it was common for PCs and XTs to have power supplies with capacities ranging from 85W to 150W or so, then I'd say it's reasonable to assume that the system unit won't draw much more than 1.2 amps. If you are limited to 3 amps of current, that leaves you 1.8 amps for a monitor.

[lafos]

Don't forget PSU efficiencies weren't very high back then. A PSU that gives 130W out probably uses close to 200W. A FH hard drive can pull 12V 4A during spin-up, depending on the drive. OTOH, a Seagate ST238R half-height drive works happily in my IBM 5150 with its 63.5 W PSU.