I recently had the displeasure of working on a Gateway G6-400. I’ll relate some of the experiences here, in case you ever have the same misfortune.
The G6-400 looks good on paper. This particular configuration had a P2-400 in it on an Intel mobo (BX chipset), a 16-meg 3dfx video card (hot for the time), and a DVD drive. The owner complained it was slow and unstable. The usual cure for that is to remove the extra crap Gateway installs on all their PCs.

Unfortunately, this one wouldn’t boot to let me do that. Not even in safe mode. Nice, eh?

Memory problem? I tried several known-good DIMMs. Same results.

Power supply? I tried a known-good, brand-name power supply. Same results.

At some point, the hard drive made an ominous noise. I replaced the hard drive and attempted a clean install of Win98SE. It bombed out at random points during installation. Just in case it was the DVD drive, I tried several different CD-ROM drives. (Hey, I was desperate.) Same result.

Out of curiosity, I put the suspect hard drive in another computer and tried to boot it in safe mode (I didn’t want Windows to mess up the configuration). It worked fine. Rats.

So by now I’d replaced everything in the box–everything important, at least–except the mobo and the processor. I spied an FIC P2 mobo with a BX chipset at Software and Stuff for 30 bucks. I bought it. I was playing the odds. Mobos go bad more often than CPUs do, especially when you’re not overclocking. And if I was wrong, I have other Slot 1 processors. The only other Slot 1 mobo I have is one of the really old LX-based boards that only has a 66 MHz bus.

Why pay $30 for an obsolete mobo when you can get a modern board for $50 or $60 and put a nice Duron or Athlon CPU on it? I doubted the power supply would handle it well. Spend $30 more on a mobo, and $30 more on a new CPU, then you have to replace the power supply as well. Suddenly $30 more has become $100.

The FIC is a much nicer board, even though the specs are very similar. It has one more DIMM slot than the Intel board had. It has no onboard sound, but it has one more available PCI slot. Expandability comes out a draw (you’ll use the extra PCI slot to hold a sound card), but you get your choice. You can put in something equivalent to the midrange Yamaha sound built into the Intel board. Or you can put in a high-end card. The board itself has a lot more configuration options, and even with the default options it boots a lot faster.

This G6-400 has a microATX power supply in it. At least it looks like a microATX power supply, and a lot of people who sell eMachines-compatible microATX boxes claim they’ll also fit a G6. Why Gateway put a small-form factor, low-power power supply in what was at the time of manufacture the second-fastest PC on the market, I have no idea. Unless the idea was to make lots of money selling replacement power supplies. The plus side is, at least it really is ATX, unlike Dell, who uses something that looks like ATX but isn’t. (You’ll blow up the mobo if you plug an ATX power supply into a Dell mobo or a Dell power supply into a standard ATX mobo.)

Fortunately, this case has screw holes in the standard ATX places as well. Unfortunately, the opening in the back isn’t big enough to accomodate any standard ATX power supply I’ve ever seen (the opening blocks the power plug). Someone willing to resort to violence with a hacksaw, Dremel (or similar tool), or tin snips could hack an opening big enough to accomodate a replacement box. More on that in a bit.

I pulled the Intel mobo and dropped in the FIC replacement. Unfortunately, the case used one big block for all the case switches. Since nobody’s ever standardized the header block for the and reset switches and lights, that’s a problem unless you’re replacing boards with a board from the same manufacturer (assuming manufacturers never change their header block pinouts, which isn’t exactly a safe assumption). But that wasn’t the only problem I ran into with this motherboard swap.

Remember that power supply I told you about? Turns out the power lead on it is just long enough to reach the power connector on the Intel mobo the machine came with, in front of the memory slots. FIC put its power connector on the other side of the CPU, and the cable is about half an inch too short to reach. Good luck finding an ATX power extender cable. Directron.com has one for $5, but the minimum order is $10 and that’s before shipping. A search on Pricewatch.com only listed a couple of places having them. Pricing was under $10, but then there’s shipping. I found one computer store in south St. Louis County that had ONE in stock. “They’re not cheap,” the salesperson warned me. I asked how much. $16.95. “You’re not kidding,” I said. That’s half the price of a new 300W power supply. Of course, by the time you pay $5 online and $10 to ship it, $16.95 looks a lot more reasonable, doesn’t it? And if your case won’t accomodate a standard ATX power supply, either buying one of these or buying a similarly overpriced microATX power supply may be your only choice.

To get things up and going, I just jerry-rigged it. I ran the power cables and found a place to rest the power supply where it wouldn’t short out anything. Then I shorted the power leads on the mobo with a screwdriver, and booted Windows 98 in safe mode. It booted up just fine, after insisting on running Scandisk. I booted into regular mode, which insisted on running Scandisk again. It worked beautifully. I did some very minor optimizations (Network server in filesystem settings, turning off Active Desktop, etc.) and rebooted a few times. No problems. No weirdness. Everything was smooth and fluid.

The chances of me ever buying a Gateway (new at least) already approached zero before this adventure. The few Gateways I dealt with in my years doing desktop support always had goofy problems that I usually had to reinstall the OS to resolve. Meanwhile, the Micron or Dell in the next cubicle over kept on chugging away, never needing anything more than basic maintenance.

This motherboard swap is easily the most painful swap I’ve ever done. It worked in the end, but the power supply was an annoyance and an unplanned expense. The header block was an annoyance.

So if you’re thinking about a motherboard swap in a Gateway, particularly a G6 series, don’t plan on it being a walk in the park.