The VX chipset can handle 512K L2 cache but it´s also limited to 64MB cacheable RAM area. The question is if 256K ist sufficient to max out those 64MB or if 512K have any benefit at all.

You should populate the board with 64 or 128 MB RAM and run a tool like "ctcm7" - this will tell you if there´s a 64MB cached area or if there´s any non-cached area.
If ctcm7 finds that the cacheable area is for example only 32MB it would be useful ton replace the cache chips. Otherwise it´s a waste of time.

wouldn't the cacheable area be determined by the tag ram size ? ie. the ISSI chip between the NB & SB.

majestyk wrote on 2022-06-11, 16:14:

The VX chipset can handle 512K L2 cache but it´s also limited to 64MB cacheable RAM area. The question is if 256K ist sufficient to max out those 64MB or if 512K have any benefit at all.

You should populate the board with 64 or 128 MB RAM and run a tool like "ctcm7" - this will tell you if there´s a 64MB cached area or if there´s any non-cached area.
If ctcm7 finds that the cacheable area is for example only 32MB it would be useful ton replace the cache chips. Otherwise it´s a waste of time.

I see. ctcm on my 64MB saying "no noncacheable Areas found" - does it mean that everything is maxed out and there is no sense to upgrade board at all?

TAG-RAM size and organisation must match the respective L2 cache-size of course.
The cacheable area is limited by the chipset here. Intel 430 VX has a fixed limit of 64MB, same goes for 430FX and even the later 430TX. Only the (more enterprise) 430HX provides 512MB cacheable area under the conditions that you have 512k L2 cache and 2 (two!) TAG-RAM chips.

Generally the amount of necessary L2 cache for a given cacheable area depends on the chipset design, cache-policy, write-back/write-through etc.

"No non-cacheable areas found" means that - under the current cache-policy etc. - 256K are all you need.

No. All Intel chipsets for socket 5 and 7 caches up to 64MB with a exception: HX chipset with 11 bit tag sram (two tag sram chips) can cache up to 512MB.

Cheers,

LX caches up to 192MB, and NX up to 512MB...if you dare to use them. LX was mostly socket4, but I think there were a few used on socket5 too...right?

-Max ram is 128mb

-Max motherboard cache is 512k on motherboard +\ or coast

Max cachable is 64mb

I once tried to get more ram than 256mb in a 430tx mobo and it failed. There doesn’t appear to be any way to do it, and I expect it’s the same case with the 128mb limit of 430vx

I don’t think there is a way around the cachable area (except the way I will discuss in a second), but majestyk is probably the one to talk to about that.^

The 512k I’m pretty sure with the right chip and configuration you could achieve. You would have to study the traces and the datasheet of some 128KB modules.

Okay, here is the thing though,

That cache probably doesn’t even matter because if you use my method you might disable it anyway (and be faster for it) though testing will determine that.

Anyway, I speak of course of the k6-3, the k6-2+ and the k6-3+

With these cpus the caching problem basically goes away.

Ultimate retro link btw. Let’s be sure to fix any errors in the listing with info we learn here.

https://www.ultimateretro.net/en/motherboards/3482

Does yours have one or two heatsinks below the cpu?

If one then your fastest cpu is a mmx overdrive 200 or if you wanna get janky, you could do a k6-233.

Any more than that and you’ll need a power interposer. Or to supply voltage to the traces that appear to be present on the mobo for vcc2

More info
https://www.anandtech.com/show/72/7

Sphere478 wrote on 2022-06-12, 02:23:

Does yours have one or two heatsinks below the cpu?
If one then your fastest cpu is a mmx overdrive 200 or if you wanna get janky, you could do a k6-233.

My mobo does have two heatsinks, so I am good to go with 233 CPUs.

GoldenPentium wrote on 2022-06-12, 02:53:

Sphere478 wrote on 2022-06-12, 02:23:

Does yours have one or two heatsinks below the cpu?
If one then your fastest cpu is a mmx overdrive 200 or if you wanna get janky, you could do a k6-233.

My mobo does have two heatsinks, so I am good to go with 233 CPUs.

That’s great news.

Actually I was thinking more along the lines of a k6-3, k6-2+, or a k6-3+.

Are you open to that? You would probably be able to reach 400-500 mhz with one. And your cache issue wouldn’t be a problem anymore because of the onboard cpu cache.

Can you measure the middle corner pin on the cpu socket using a resistor leg to ground (black wire on psu connector, or the case) without a cpu in it when all of your voltage setting jumpers are removed?

Sphere478 wrote on 2022-06-12, 02:56:

Can you measure the middle corner pin on the cpu socket using a resistor leg to ground (black wire on psu connector, or the case) without a cpu in it when all of your voltage setting jumpers are removed?

73-75 Ohm, if I measured it in a right way.

Dc voltage. Turn it on

I think I figured out the answer though. Were I not tired last night it might have been obvious to me, Your heatsinks are large and that suggests linear regulators. And obviously the lack of inductors does as well.

And the manual has options down to 2.5v

This is low enough for a k6-3

Not a k6-2+/3+ Though.

You can map your various resistor combinations and see what you can come up with though as far as undocumented settings but if that doesn’t work. With some resistor mods you may be able to get to 1.9-2.1v which is where a 2+/3+ would be happy. If you want to look into that then you’ll have to check specs of your regulator controller, and regulator and find the resistors responsible for making the voltage setting and change one to one you want or make a jumper with one on the jumper if higher resistance is a option.

In any case, 2.5v will be enough to accomplish your goals.

You will want to watch the regulators for heating though. Be sure they are cooled.

Unless you want to go for a 2+/3+, your next step is to find the 2.5v setting, order a k6-3 and get a bios update from the diy modding support thread and you should be good to go.

Re: Diy modding support for k6+And 120gb hard drives into bios roms

I’ve exceeded motherboard memory limits in the past.

In a few cases the board would count the extra memory but not use it.

I had a later IBM 286 of some sort with 20mb installed it counted up but still a tad less than 16mb was usable

rmay635703 wrote on 2022-06-12, 17:49:

I’ve exceeded motherboard memory limits in the past.

In a few cases the board would count the extra memory but not use it.

I had a later IBM 286 of some sort with 20mb installed it counted up but still a tad less than 16mb was usable

My 430hx tyan can count 768mb and post but when it tries to use it the system crashes.

Another user around here was able to get 384 on their 430tx mobo but same problem.

In both cases memtest says all is well.

The only way you can see the issue is to fill up the memory with unique data. Like unpacking driver.cab usually does the trick. Trying to install windows or a OS also usually fails half way through.

This is because detecting and being able to use aren’t the same thing.

There may be mobos that will allow the usable memory only to be used but these two examples led to a unstable system. Removing the unsupported memory solved the peoblem immediately.

rmay635703 wrote on 2022-06-12, 17:49:

I’ve exceeded motherboard memory limits in the past.

In a few cases the board would count the extra memory but not use it.

I had a later IBM 286 of some sort with 20mb installed it counted up but still a tad less than 16mb was usable

fyi, a 286 can only have 16MB total memory (EMS not counting), of which some is used for ROMs and some VGAs might use 1MB for Framebuffer from 15-16MB (i've read somewhere)