Can you type out all the markings on your UMC northbridge and southbridge chipsets?
Do you have a HOT Shuttle 433 rev. 4? Rev 4 supports EDO. I suspect your chipset reads something like UMC8881F-Exx, the E is for EDO. How'd you land a rev 4 board? I'd like to get my hands on one. I only have rev 1-3 which is Cyrix 5x86 flakey. Unfortunately, the Rev4 boards only have 4 cache DIP sockets, thereby supporting up to 512KB cache only.
I have also rev 1.x-3.x motherboard! (: Here you are all the markings from chipsets:
northbridge:
UM8881F
9521-BTS
124040
southbridge:
UM8886AF
9536-AYS
N503B6
Check to see if your ps/2 mouse port connector works. I was never able to get it working on rev 1-3.
Sorry, I don't have PS2 cable connector. If I had one I would gladly test it for you.
AMI BIOS's usually let let you set write-thru cache, so w/512KB cache, you'd be able to cache up to 128 MB of RAM.
Thank you for your advice! I used to use 512kB cache on this motherboard for a long time but it was set to write-back mode and I had installed 64MB of RAM.
BTW
Have you ever seen award bios on Shuttle HOT-433? If no, here you are some screens:
EDIT:
I have retested all my UMC based motherboards, the results are:
my second HOT-433 1.x-3.x
northbridge UM8881F
9524-BTT
126380
southbridge UM8886AF
9520-AYA
N408D6
BIOS 433AIP16
EDO support YES
my third HOT-433 1.x-3.x
northbridge UM8881F
UM8881F
9525-BTA
125870
southbridge UM8886AF
UM8886AF
9536-AYS
N509F5
BIOS 433AIP16
EDO support YES
my fourth HOT-433 1.x-3.x
northbridge UM8881F
UM8881F
9525-BTA
125880
southbridge UM8886AF
9540-BYS
R521B0
BIOS 433AUE23
EDO support YES
GA-486am/s rev 2.1A
northbridge UM8881F
9516-BTO
123800
southbridge UM8886AF
9520-AYT
N407D5
BIOS JUNE 1995
EDO support NO
GA-486am/s rev 2.21
northbridge UM8881F
9523-BCT
N43037
southbridge UM8886AF
9540-BYS
R530C1
BIOS 7 NOVEMBER 1995
EDO support NO
ECS UM8810PAIO rev 2.1
northbridge UM8881F
9521-BCT
N42648
southbridge UM8886F
9520-EYS
R40360
BIOS VBS1.11PH
EDO support YES
Last two motherboards have similar signing on northbridge "BCT".The important thing is that one before last motherboard in contrast to last motherboard doesn't support EDO memory!
What doesn't kill you makes you stronger.