First post, by Inrit
Hi there,
I have a 486 with the Abit AT425 motherboard, you can see the specs here:
https://stason.org/TULARC/pc/motherboards/A/A … 5-AT433-AT.html
There's very little information online about this motherboard as best I can find. It had an Intel 486 SX25 CPU in it, which I attempted to upgrade to a DX50 chip. The new chip works fine, but is recognized as 25mhz, and benchmarks show that it's only operating at around 25mhz as well. There were no jumpers listed on that info page to actually set the speed of the CPU, and there are no such settings in the bios, so I assume it's using some built-in 25mhz default. I don't see any unaccounted-for jumpers on the physical board that aren't on that Stason page, either.
I did set the "80486DX" cache jumper setting (on the linked page), and the system does show up as "DX" on boot, but still 25mhz.
I'm afraid the speed might be unchangeable.
Has anyone ever seen something like this? I've never seen a 486 motherboard with no upgradeability, and I took the AT420/425/433/450 branding to mean that this motherboard could support all those speeds, but now I'm worried that those might all be bespoke motherboard editions with a single speed.
Would love any thoughts and ideas!
Thanks.