Resurrecting an Socket 3 motherboard (Soyo SY-25N)

Topic actions

Reply 40 of 41, by keeper5511

Posted on 2025-09-12, 20:54

keeper5511 Offline

Rank Newbie

Rank: Newbie
Posts: 35
Joined: 2024-03-25, 13:28

I have found the problem!!!! So far I used EDO ram (double sided) but today I test with FPM single sided RAM motherboard works like a charm!!!!!

Reply 41 of 41, by Chkcpu

Posted on 2025-09-13, 15:35

Chkcpu Offline

Rank Oldbie

Rank: Oldbie
Posts: 612
Joined: 2021-05-13, 18:42
Location: The Netherlands

keeper5511 wrote on 2025-09-12, 20:54:

I have found the problem!!!! So far I used EDO ram (double sided) but today I test with FPM single sided RAM motherboard works like a charm!!!!!

This is great, congratulations!
Yes, most 486 boards/chipsets don’t support EDO RAM. Only a hand full of 486 PCI boards with a later revision chipset do.

These 486 Award BIOSes are not compressed but always copy their contents to shadow RAM. With EDO RAM, this process must have scrambled the BIOS copy in shadow RAM in such a way that it even produced random POST codes. Curious. 😉

Greetings, Jan

CPU Identification utility
The Unofficial K6-2+ / K6-III+ page

Go to top of page Go to top of page

Back to General Old Hardware