Yeah, there's a huge fan welded to the bottom of the ATX PSU. While I could slide the AT PSU in, there's a metal bar across the case that blocks the ATX from going in-- partially because of the slightly taller nature of the ATX, but also this huge fan. Unfortunately, like some other computers I have, you can't take this little metal bar off to fit things through.
Oh well, I guess this'll just wait until I get another AT PSU.

MrKsoft wrote:

Yeah, there's a huge fan welded to the bottom of the ATX PSU. While I could slide the AT PSU in, there's a metal bar across the case that blocks the ATX from going in-- partially because of the slightly taller nature of the ATX, but also this huge fan. Unfortunately, like some other computers I have, you can't take this little metal bar off to fit things through.
Oh well, I guess this'll just wait until I get another AT PSU.

Yup, you'll need one of those that have only an 8cm fan in the back and openings in the opposite direction (not below, or it will be blocked by said plate!).

I had a GA-5AX which was unstable but worse, Windows 98 refused to install, no matter what hard drive i used, when i started the setup, it got an error and quit to dos, I put my SD card with DOS installed and tried some software out and it locked up and was very unstable, i payed $200 for that board, i asked for a refund and i got the money back and got a intel AN430TX board for cheaper than the GA-5AX and it was more stable and Windows 98 installed fine on that unlike the GA-5AX

Wow, talk about a necropost. Was rather surprised to see this old thread again.

Never really figured out what was up with it. Power supply seems fine, I ended up running a 486 off it for a few years. Right now it's back with the GA-5AA in the same case as originally described here, but I have a Pentium MMX 233 in it instead alongside a Matrix Millennium II, Voodoo1 and an AWE64 value (kind of wasting the potential of a Super Socket 7 board but my other S7 boards either don't support MMXs or are made by PC Chips 😉 ). It seems stable enough in Win95 but I haven't done much DOS testing. But I didn't notice any issues.

At this point I just associate it with some edge case of my hardware configuration at the time and the Aladdin V chipset.

MrKsoft wrote:

Wow, talk about a necropost. Was rather surprised to see this old thread again.

And I'm going to resurrect it again! I'm trying to set up a vintage gaming machine using found parts. I'm using a GA-5AA - seems like a nice board, currently with a K62-350 which is detected and works fine. I do have a known working K62-500 cpu which I am trying to get to work in this motherboard, however it's detected at 250Mhz by the BIOS. Same problem as the OP. I have upgraded to the BIOS to F6 which hasn't helped. There is a beta (F7b) BIOS that I have not tried yet. I double and triple checked the jumper settings - they are correct according to the documentation. Maybe the manual is wrong. Anyone have any ideas? https://www.gigabyte.com/Motherboard/GA-5AA/s … #support-manual I appreciate that Gigabyte keeps all their old docs/files online.

Hey nullvalue!
Can you post a picture of your motherboard configured for the 500MHz CPU?
What CPU speed is reported in memtest or diagnostics programs?

Honestly I think the jumper configs in the manual are inaccurate. I had similar issues trying to get the speeds I wanted with the K6-2 (I believe that's how I ended up at 250 once, I was going for 450). I know there are multiple board revisions so the manuals out there may only apply to the latest version? Might just have to experiment until you get what you want.

MrKsoft wrote:

Might just have to experiment until you get what you want.

This is probably what I'll have to do. This couldn't possibly damage anything could it? As long as I'm only changing the freq switch?

I'm having some similar buggy issues with this board and may have some answers soon as I see this mystery is as of yet still unresolved.
I have been having a discussion with Jan (the guy behind the k63+ bios mods) and he mentioned in passing that the latest bios for this motherboard has been reported to be unstable. I am about to try a bios downgrade.

I have had a lot of bugs that I was able to track down to the sata card not being in slot 1, so to any reading this you may wanna check that.