Attached are the 2 screens one with the 2.1 board with 166 and 512 cache and the other is the 2.3 with 200 and 256 cache..

- change JP7 to set 512KB cache, but you need 6464 chips on board for that to work, not the 3232 ones
- pull out half the ram, right now half is uncached and afaik Windows is using the slower half first
- both 1.x and 2.x boards should support 3x multiplier, all you have to do is open JP9

Will try that later on.. thanks!

Curious tho.. 2 more questions.. how come the 4 32mb chips worked fine in the 2.1 board but not in the 2.3? I have jp7 on and jp9 off.. I never thought to remove 2 of the rams cause it was working in the 2.1… im at work for a few more hours.. will try removing them later..

Also will 64mb chips work? I seen in the manual
Says up to 32mb. I found some 64mb chips on eBay.. didn’t want to buy unless this worked… hoping it does..

Thanks much

Hi,

the earlier revisions of the board don't allow to pull the BF pins high. So without a mod it is only possible to use a Pentium MMX up to 166 MHz.
With a rather small mod it is possible to use the MMX200 and MMX233 as well.

More details can be found on the following website (not mine, just found while looking for information for my board):
https://www.vobarian.com/8500tvx.html

1. I did remove the mem and it didn’t change anything.. still 256 on the cache.

2. So it would appear my multiplier isn’t working? Is that responsible for the 256/512 cache issue I’m having?

Thanks

I reread that post… I have the 2.3 board with the mmx200. I guess I could do the mod on my 2.1 board and it’ll solve the problem…

What I’m not understanding is how come the 2.3 won’t allow me to have 512cache.. I suppose it could be due to memory being 4x32, but I had those in my 2.1 board and had 512.

Many motherboards from this era had a combination of L2 cache chips soldered to the motherboard and a slot where additional cache could be added. The PCChips M520 I have has fake L2 cache chips on it, and it had an empty cache slot - that means that whoever was forced to use this computer had to live with substandard performance as it had no L2 cache at all! With the cache slot, L2 cache could be added to the board, but that can be expensive and difficult because COAST modules can be very picky about what boards they work on. I went with an Evergreen Spectra adapter and a K6-3+.

In your case it seems your board has a pair of 128k cache chips and no slot to add more, so (short of heroic measures such as replacing the cache chips with larger ones) you are stuck with 256k L2. Here is a thread where another person with a VX chipset board wanted to know about this. 430VX cache size

Thanks repo… kinda what I figured.. not willing to desolder those chips.. I’m prob gonna modify my 2.1 and keep the 2.3 as a spare..

Thanks for the explanation

Fas82 wrote on 2024-09-27, 18:32:

how come the 4 32mb chips worked fine in the 2.1 board but not in the 2.3?

I didnt mean that 128MB disables your cache. I meant the other way around - having more than 64MB of ram is making your computer slower 430VX chipset and cacheable memory running from uncached ram slows you down around as much as ~one CPU grade.

Fas82 wrote on 2024-09-27, 18:32:

I have jp7 on

then most likely board doesnt have 512KB of cache? read the print on cache chips

Fas82 wrote on 2024-09-27, 18:32:

and jp9 off..

Skorbin and his link explain that one.
"The original Pentium had internal pull-up resistors on both BF0 and BF1. Since these are high by default, I guess Biostar saw no reason to provide a way to force them high, so the old versions of 8500TVX cannot set a pin high, they can only set it low or not set it at all (letting the high default take over)."
older board requires simple mod

Fas82 wrote on 2024-09-27, 18:32:

Also will 64mb chips work? I seen in the manual
Says up to 32mb. I found some 64mb chips on eBay.. didn’t want to buy unless this worked… hoping it does..

You should want LESS not more ram. No matter how much Cache you will have enabled on this board more than 64MB will be _slower_.

Hello.. thank you all for the insights…

Ended up modifying the 2.1 board with the resistor. So now it’s 200mhz with 512 cache.

The 2.3 board cache chips are diff from the 2.1. 2.3 has 3232AF chips, the 2.1 is 3264F chips. Just weird to me that the manual says u can change the cache and it’s a newer rev… but obv they fitted the 2.3 with 256.

Got some good insights into this little side project. And hopefully this helps something else down the line…

Thanks again!

Good morning. I have 2 identical boards. V 2.3 . One of them is dead. In post analyser card voltages is ok clock is working reset also. Cpu voltages are correct. But no post code just lines. I try the bios chip cpu and jumper settings from the working board but nothing. Any suggestions? Thanks

You should want LESS not more ram. No matter how much Cache you will have enabled on this board more than 64MB will be _slower_.

That is not always true.
The user manual says that in 512KB configuration (plus the relevant TAG module), this MB can cache up to 84MB instead of the standard 64MB with 256KB cache.
Also, depending on App, more ram can still help.
From my experience with this motherboard /256KB cache variant, I got less frame drop in UT99 with 80MB than in 64MB...