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Cheap Machines: The HP/Compaq dc7900

Front View On Steampunk Table - 500 Wide.jpg

Back in the early oughts, I saw my first ultra-small form factor (USFF) PCs at our doctor’s office. The machines were Dell Optiplex SX270s, and they were little marvels: Quiet, fast, easy to field-strip and very reliable. (There was a certain widespread problem with bad electrolytic capacitors in that era, and I ran into a couple of SX270s and Samsung monitors containing said bad caps.) They were P4s running XP, and Carol used one successfully as her main machine for a number of years. We donated several to our church’s office, which was pretty full and rather tight, space-wise. Nobody had any trouble with them. Even in 2007, they could be had for $200 or less, depending on what they had in them in terms of RAM and HD.

The SX270s were 2001-era machines, and I’ve long since gotten rid of them. I had a couple of slightly later models, including the SX280 and GX620. I took the 620 to the Taos Toolbox SF workshop in the summer of 2011, along with my steampunk computer table and my Aethernet Concentrator, as Jim Strickland dubbed it. It mounted behind the monitor, and while that made it a little tricky to plug in thumb drives, it made very good use of what small space the table offered.

The steampunk computer table is still in my office, and if I ever go to another live-in workshop again, I’ll take it with me. The GX620 ran Win7 badly, and has been gone for several years now. I need a newer machine to go on the table. Notice I didn’t say a “new” machine. In fact, I was a little curious as to how cheap a machine I could get on eBay that would do the job (office apps) and mount to the dual arm monitor stand that I have clamped to the table. That meant a machine with VESA holes, ideally. Such exist; I had seen them years ago.

It didn’t take long to find such a machine: The HP/Compaq dc7900 USFF. At 10″ X 10″ X 2.75″ it’s a little smaller than the SX270. And the price, hokey smoke! I bought one for $37. Now, that didn’t include a hard drive, but I have a box full of empty SATA hard drives. It came with a DVD-RW drive (and LightScribe, at that, heh) 4GB RAM, and an outboard 135W power supply. The CPU is a 2.5 GHz dual-core Pentium E5200.

Cropped Front View dc7900 - 500 Wide.jpg

I installed Win7 on it, and boom! It just worked. It identified the Dell E228WFP monitor I had attached to the monitor stand and adjusted its resolution to match. I installed enough software to test it but no more than that; like I said, I don’t need it right now and it was mostly a research project and a bit of a stunt, to see how much machine I could buy online for how little money.

Below is a side view of the setup. I used four M4-10 screws to mount it to the monitor stand (VESA is a metric standard) and twisted the arm around until the dc7900 was level with the top edge of the monitor.

Side View - 500 Wide.jpg

Internally, the machine is uncrowded, with two small and almost silent fans to pull air past the CPU heatsink and out of the machine generally. It has eight USB ports, plus both PS/2 keyboard and mouse DIN connectors.

Interior Closeup - 500 wide.jpg

The hard drive is mounted underneath the optical drive, but both come out very quickly without any screwdriver involvement. The hard drive is screwed into a little spring-loaded caddy that snaps into place and mates the SATA connectors firmly, with a little constant spring pressure to keep the drive from walking out of electrical connection.

I’ve only been messing with it for a few days, but so far it’s been trouble-free and able to do anything I could throw at it. No, it’s not as fast as my quadcore. I won’t be doing any gaming or video editing on it. Word processing and email don’t take a lot of cycles. Web browsers are wildcards in that regard, but so far it’s been able to render YouTube videos without any stutter or artifacts.

If you need a physically small machine for ordinary office work, I recommend it. And hey, for $37 plus a junkbox SATA HDD and an OEM copy of Win7, I’d say it’s hard to beat.


  1. Bob says:

    Pretty slick.

    “I installed Win7 on it, and boom! It just worked.”
    Curious about this. The license would seem to cost more than the CPU. Can you transfer the license from one of your junked machines?

    I like your steampunk table especially the pipe carrying handle 🙂 But one of my main requirements for a computer table is height adjustment. I think good ergonomics is for my elbows to be close to a 90 degree angle while I am typing and for my eyes to be about 30 degrees below horizontal while looking at the center of the monitor. This requires that the table be close to my lap–lower than most tables. I also require an adjustable chair but that’s a whole other story.

    1. I buy OEM copies on eBay, and they send me the usual dead hard drive to keep it nominally legal. I don’t think you can transfer an OEM install from machine to machine. This machine had Windows on it before, so in truth the machine’s owners (myself and whoever owned it before) have paid the “Windows tax” twice.

      I designed the table to a specific height: The work surface is 26 1/2″ off the floor, just like my main computer table. That took a little fiddling with the pipe fittings making up the legs, and in truth I was lucky to get so close to the design height without actually cutting and rethreading pipe. I had a local furniture shop cut and finish the wood slab for me custom. I sometimes think I should have made it just a couple of inches longer, but I found it to be completely workable for the two weeks I spent with it in Taos.

    2. Amy says:

      I bet one of those dc7900’s would do great with Ubuntu installed on it. I might look into one if I ever decide I need a proper desktop system for my boudoir. 🙂

      1. One of the cool low-tech features of the dc7900 is that it has VESA standard threaded holes on both the top and bottom panels. (They’re the 10 cm square spacing, and I think the screws are M4-10s.) This makes for many interesting possibilities for mounting the thing.

        I seriously doubt even the most recent versions of Linux will have any trouble running on a dc7900. Like I said, I have another machine with a similar CPU with Mint 18.3 Cinnamon on it, and it works like a champ.

  2. TRX says:

    “Off-lease” computers of that general class show up on eBay, Tigerdirect, etc. regularly. I’ve been paying anywhere from $20 to $80 for them. I have a client who uses them as (basically) smart terminals for a server application.

    Also note that older laptops are commonly available in the $50-$100 range; at that price point, dropping one or having it stolen is only an annoyance.

    The pre-2007 processors also lack the hardware backdoors the later ones do. The Internet might go down in flames when the ME exploit finally gets out to the script kiddies, but they’ll still be running. Though they might have some problems with suppliers, customers, and banks…

  3. RH in CT says:

    So how many times more expensive was the dual monitor stand than the computer? It looks like one is a hundred bucks or so at Monoprice.

    1. Yup. The Mount-It stand was $113.49 through Amazon, back in 2017. I consider it long-term infrastructure (unlike computers, which have limited lives) and because it’s a clamp model, it’s not married to that particular table. I don’t mind paying more for stuff that will likely last a long time.

  4. Christian R. Conrad says:

    Wow, what a huge keyboard! Or… Ah, what a small desk — and above all, monitor. (I find that with increasing age [and correspondingly decreasing sharpness of eyesight], everything under 27″ feels pretty darn small.)

    But what I was really going to ask: What’s the pipe at the lower left for, the one that sticks out towards the rear from the front left leg, with a vertical T-fitting at the end? Intended for cable routing or something like that?

    1. The keyboard is a Northgate Omnikey 101–which is one of the smaller ones in that product line. I’ve been using them since the early 1990s and still use them. Some of the ones I have I rescued from the junkpile when Coriolis went under, and they still work. They’re now valuable enough to repair if they malfunction, and I have one with a dead key that I should probably get fixed while there are still people willing to fix them.

      The pipe you mention is there to support a pipe mast going up to a parabolic reflector Wi-Fi antenna. Here’s one entry you should read:

      This entry, about the Taos Toolbox writers workshop, contains a photo:

      The workshop was in fact the reason I built the table and the concentrator, so I would have a small but comfy workstation during the two weeks we were there.

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