I have finished running some tests. They were not successful. Quick recap: 60 FSB, P75 chip, 3x multi. I tried all available voltage settings. For the 3.47, 3.6 and 4 voltage settings, I saw the BIOS POST display OK! However, for these 3 tests, they all froze at exactly the same time and place: on the "starting MS-DOS" line.

I then increased the voltage to 5V, but I saw no BIOS POST display. That's really strange, I think. I wonder - have I misread the manual? Am I seeing the voltage jumper pins round the wrong way? I wonder if I am setting the voltage to the 3-4 volts options, when it should be the 5 volt option, for instance. Even with the manual, it's not completely clear which way around the pins are.

I tried an Intel DX4-100 (WB model) in the board, and it works, but the L1 cache appears to be fixed using WT mode. If I enter the BIOS set up area, I cannot adjust the L1 option to change it to WB, because this option is "grayed out/disabled looking".

I attempted to run the DX4-100 @ 50 FSB, but just after the BIOS POST display said "Starting MS-DOS...", it then said something like "Bad or missing command prompt interpreter". I tried 3.47, 3.6 and 4 volts. I did not try 5V, because I don't want to kill my only DX4-100 chip!

What jumper setting did you use for that DX4? If you used the one labelled specifically for the "Intel DX4-100" there's a good chance that it doesn't allow wrtieback cache (since the standard Intel DX4 only supported write-through)...

I think you're right! But the curious thing is, I think the manual is missing the jumper settings for the DX4-100 WB model. Conveniently for this discussion, the jumper settings can be seen online, here. If you scroll down, you can see the DX4-100 configuration, but as you suggest, this is likely to be for the WT model.

At the bottom of that webpage, it mentions that jumper J22 is used to set the L1 cache to either WT or WB. Looking at the DX4-100 jumper settings, J22 is not set to anything. I wonder if it's possible to simply add a jumper to J22, for either WB or WT? Please note that ATM, this is not an important project. I'm happy with the AMD P75 @ 160 MHz (currently installed), and I'm also happy with the Asus PVI-486SP3 running the Intel WB DX4-100 @ 120 MHz (40 FSB). Thanks. 😀

Try the P24D jumper setup for iDX4-WB

Don't forget the Intel DX4-100 wb is much more rare then the (common) Intel DX4-100 wt. I got around 6 5x86's + 4 of those upgrade chips and a whole number of Intel 100's...but NONE of them the elusive wb version.

Better not burn it, you might not be able to replace it

Yes I am lucky. I didn't realise the chip was a WB model. It came with an Asus PVI-486SP3 board, from ebay. There must have been a temporary dip in the market, because I only paid 5 euros + shipping for it, and the board was the 1.8 revision. Topic here.

It's possible that the user report about this board is true, and that it won't run a DX4-100 correctly. I set the jumper configuration to the Intel P24D setting, and also set the bus speed to 40 FSB, but ChkCPU reports an odd bus speed of 26.9 MHz. It reports the multi correctly, which is 3x. It also reports that the L2 cache is in WB mode. It also reports the correct CPU Id, and that it's a DX4-100 WB enhanced chip.

But as the bus speed has mysteriously dropped from 40 to 26.9, I only get a clock speed of 83 MHz. Ah, wait a minute. Isn't that the speed of an Intel Pentium overdrive chip?

Solved! I have successfully set this mobo's jumpers to enable the iDX-4 WB model. I set the jumpers to the "standard" WT DX4-100 setting, and then added one more jumper myself. This new jumper goes on the J22 jumper. It goes in the 2-3 pin position. Perhaps I should write to the manufacturer of this mobo, with an important update for their printed manual? 😉 I run 3DBench, and get 90.9, which used a S3 Nitro GX 4MB PCI video card.

I ran PcpBench.exe, using 8-bit colour, and got the scores below. All 3 tests ran in the "slower" NoLFB mode. I wanted to activate LFB mode, to see if my scores improved, but neither FastVid.exe nor MTRRLFBE ran successfully. Whatever option I chose inside FastVid, it crashed when I exited the program. When I tried to run MTRRLFBE, it seemed to complain that the .exe was missing a .zip file.

Mode 100 (640x400) 10.4
Mode 101 (640x480) 9.1
Mode 103 (800x600) 7.0

retro games 100 wrote:

Solved! I have successfully set this mobo's jumpers to enable the iDX-4 WB model. I set the jumpers to the "standard" WT DX4-1 […]
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Solved! I have successfully set this mobo's jumpers to enable the iDX-4 WB model. I set the jumpers to the "standard" WT DX4-100 setting, and then added one more jumper myself. This new jumper goes on the J22 jumper. It goes in the 2-3 pin position. Perhaps I should write to the manufacturer of this mobo, with an important update for their printed manual? 😉 I run 3DBench, and get 90.9, which used a S3 Nitro GX 4MB PCI video card.

What I do is this:
I've got the whole th99 in my offline database (the one with the pics) and edit the pages of the boards I've found unofficial jumpersettings in so I can find them back after who knows how long.
Left or right, I always keep notes of info like this, including the info I find on the web. I download -all- info that might ever be of any use to me because when you ever need it, it might already be gone forever.

Good thinking Tetrium. 😀 Here is the manual: http://motherboards.mbarron.net/models/486pci/syl8884.htm

And I have added in the missing iDX-4 WB L2 cache jumper settings -

I reran PcpBench. Mode 100 (no LFB) = 10.4. If I configure and run univbe for DOS, PcpBench then works in LFB mode. But I get a lower score of 9.3. Strange.

I have edited page 1 of this mobo's manual, to include some undocumented FSB settings.

I decided to RTFM, and lo and behold, I've got my camera working again! For months, it was in "no flash" mode. 😦

The placement of the gameport pins is evil on this board - got shutdowns due to short cirquit a few times by plugging in ISA cards that had metal parts there before realizing. Also the BIOS chip gets in the way with some cards.

retro games 100 wrote:

I decided to RTFM, and lo and behold, I've got my

Hahaha just like with the Hubble telescope 🤣 RTFM

Does this board have an option in the BIOS for setting the PCI/CLK ratio?

Anonymous Coward wrote:

Does this board have an option in the BIOS for setting the PCI/CLK ratio?

Unfortunately, my retro fun station is now temporarily closed for maintenance, because I'm getting ready to dig out all of my junk, for a grand retest. Retro fun will be declared active again in about a week's time.

SYL8884PCI-EIO ver. 2.1
UM8886BF/UM8881F/UM8663BF/Ali M5818P
128k anonymized BIOS chip
3V Lithium Coin Cell
Made in China

AMIBIOS (C) 1994
41-P103-421183-00100111-101094-486VIP-H
(Internet says manufactured by Soyo)

[Advanced Setup]
Typematic Rate (Char/Sec): 30
System Keyboard: Absent/Present
Primary Display: VGA/EGA
Mouse Support: Disabled/Enabled
Above 1MB Memory Test Disabled/Enabled
Parity Error Check: Disabled/Enabled
Hit "DEL" Message Display: Enabled/Disabled
Extended BIOS RAM Area: 0:300/DOS 1k
Wait for F1 if any error: Enabled/Disabled
System Bootup Num Lock: On/Off
Numeric Processor Test: Enabled (grayed out)
Weitek Processor: Absent/Present
Floppy Drive Seek At Boot: Disabled/Enabled
Floppy Drive Swapping: Disabled/Enabled
System Boot Up Sequence: A:, C: / C:, A:
System Boot Up CPU speed: High/Low
External Cache: Enabled/Disabled
Internal Cache: Enabled/Disabled
Turbo Switch Function: Enabled/Disabled
Password Checking: Setup/Always
Video Shadow C000,32K: Enabled/Disabled
Shadow C800,16K: Enabled/Disabled (also CC00, D000, D400, D800, DC00)
IDE Block Mode: Auto/Disabled/2/4/8/16/32/64
IDE 32 Bit Transfer Mode: Enabled/Disabled
Primary Master LBA Mode: Enabled/Disabled
Primary Slave LBA Mode: Enabled/Disabled
Secondary Ctrl Drives Present: None/1/2
Secondary Master LBA Mode: Enabled/Disabled
Secondary Slave LBA Mode: Enabled/Disabled
Compatible Memory On OS/2 Disabled/Enabled
Init Boot PnP Devices: Yes/No

[Chipset Setup]
Auto Configuration: Enabled/Disabled
Cache Speed: 2-2-2/3-2-3/3-1-3/2-1-2
DRAM Read W/S: 1/3/2/0
DRAM Read W/S: 1/3/2/0
PCICLK-to-ISA SYSCLK Divisor: PCICLK/3 | PCICLK/4 | PCICLK/2
Keyboard Clock Divisor: PCICLK/3 | 7.16MHz | PCICLK/4 | PCICLK/2
L2 Cache Mode: Wr-Back/Wr-Thru
L1 Cache Mode: Wr-Thru (grayed out)
Main BIOS Cacheable: Enabled/Disabled
Video BIOS Cacheable: Enabled/Disabled
Resource Lock for Local DRAM: Disabled/Enabled
Host-to-PCI Post Write W/S: 1/0
Host-to-PCI Burst Write: Enabled/Disabled
Host-to-DRAM Burst Write: Enabled/Disabled
I/O Recovery Time Control: 2/4/8/12 BCLKs
LDEV# Sampling Point: 2 T2 / 1 T2
Post Write Buffer: Enabled/Disabled
Bus/Resource Lock Option: Resource/Bus
Bus Park: Enabled/Disabled
On Board IDE Drive: Enabled/Disabled
On Board IDE Speed Mode: Auto/Mode 0-4
PCI IDE Card Present On: Auto (grayed out)
PCI IDE IRQ: Edge (grayed out)
PCI Primary IDE IRQ: INTA (grayed out)
PCI Secondary IDE IRQ: INTB (grayed out)
IRQ9 Available On: PCI/PNP / ISA (same for IRQ10,11,12)
EDO RAM Read Speed: 1/0 W.S.

[Prepherial Setup]
Programming Mode: Manual/Auto
OnBoard FDC: Enabled/Disabled
Serial Port1: 3F8H/3E8H/Disabled
Serial Port2: 2F8H/2E8H/Disabled
Parallel Port: 378H/278H/Disabled
Parallel Port Mode: SPP/EPP/ECP Mode
Game Port: Enabled