256 MB is your maximum. https://stason.org/TULARC/pc/motherboards/Q/Q … ium-P55XB2.html

Sphere478 wrote on 2021-01-19, 20:34:

Hello :-) […]
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Hello 😀

So I have a p55xb2 socket 7 motherboard with two sd ram slots and four simm ram slots.

I’ve previously been able to get 256mb into it and that’s about it.

What I understand is the chipset seems to only like 256mb

Obviously I could install 2 512mb sticks but those woupdn’t work and I have tried one with 16 chips per stick before and it did not.

My question is, if I install two sd sticks 256mb each with 16 chips each can I then install 4 128mb or 64mb simm sticks and end up with more than 256mb? Recognized? I know that when you install simms and dimms you sometimes get both to recognize but with the dimm being 1/4 the size.

I’m looking for any tricks to get above 256mb

I’m going to use a k6 III+ so my cachable limit is 4gb

The memory controller in the 430TX chipset is limited to 256MB RAM maximum, there is no workaround for that .

darry wrote on 2021-01-19, 20:45:

Sphere478 wrote on 2021-01-19, 20:34:

Hello :-) […]
Show full quote

Hello 😀

So I have a p55xb2 socket 7 motherboard with two sd ram slots and four simm ram slots.

I’ve previously been able to get 256mb into it and that’s about it.

What I understand is the chipset seems to only like 256mb

Obviously I could install 2 512mb sticks but those woupdn’t work and I have tried one with 16 chips per stick before and it did not.

My question is, if I install two sd sticks 256mb each with 16 chips each can I then install 4 128mb or 64mb simm sticks and end up with more than 256mb? Recognized? I know that when you install simms and dimms you sometimes get both to recognize but with the dimm being 1/4 the size.

I’m looking for any tricks to get above 256mb

I’m going to use a k6 III+ so my cachable limit is 4gb

The memory controller in the 430TX chipset is limited to 256MB RAM maximum, there is no workaround for that .

Not quite.

Intel's official specs give it max 256MB with 64Mb chips. But... the memory controller is identical to the i440EX's and can take 128Mb chips too. So with two double-sided 256MB DIMMs, you can do 512MB.

You do need to be pretty specific with the DIMMs and chips: 16 chips with 16Mx8 structure. Fortunately, pretty much any 256MB PC100 DIMM will have this. With PC133 you need to look out for 8 chip (256Mb per chip) modules, or worse 16 chip 32Mx4 things.

dionb wrote on 2021-01-19, 21:10:

Not quite. […]
Show full quote

darry wrote on 2021-01-19, 20:45:

Sphere478 wrote on 2021-01-19, 20:34:

Hello :-) […]
Show full quote

Hello 😀

So I have a p55xb2 socket 7 motherboard with two sd ram slots and four simm ram slots.

I’ve previously been able to get 256mb into it and that’s about it.

What I understand is the chipset seems to only like 256mb

Obviously I could install 2 512mb sticks but those woupdn’t work and I have tried one with 16 chips per stick before and it did not.

My question is, if I install two sd sticks 256mb each with 16 chips each can I then install 4 128mb or 64mb simm sticks and end up with more than 256mb? Recognized? I know that when you install simms and dimms you sometimes get both to recognize but with the dimm being 1/4 the size.

I’m looking for any tricks to get above 256mb

I’m going to use a k6 III+ so my cachable limit is 4gb

The memory controller in the 430TX chipset is limited to 256MB RAM maximum, there is no workaround for that .

Not quite.

Intel's official specs give it max 256MB with 64Mb chips. But... the memory controller is identical to the i440EX's and can take 128Mb chips too. So with two double-sided 256MB DIMMs, you can do 512MB.

You do need to be pretty specific with the DIMMs and chips: 16 chips with 16Mx8 structure. Fortunately, pretty much any 256MB PC100 DIMM will have this. With PC133 you need to look out for 8 chip (256Mb per chip) modules, or worse 16 chip 32Mx4 things.

Thank you, for that, I stand corrected .
Do you know if there are typically any BIOS issues with this on 430TX boards or this something that tends to usually just work on any 430TX board ?

darry wrote on 2021-01-19, 21:24:

dionb wrote on 2021-01-19, 21:10:

Not quite. […]
Show full quote

darry wrote on 2021-01-19, 20:45:

The memory controller in the 430TX chipset is limited to 256MB RAM maximum, there is no workaround for that .

Not quite.

Intel's official specs give it max 256MB with 64Mb chips. But... the memory controller is identical to the i440EX's and can take 128Mb chips too. So with two double-sided 256MB DIMMs, you can do 512MB.

You do need to be pretty specific with the DIMMs and chips: 16 chips with 16Mx8 structure. Fortunately, pretty much any 256MB PC100 DIMM will have this. With PC133 you need to look out for 8 chip (256Mb per chip) modules, or worse 16 chip 32Mx4 things.

Thank you, for that, I stand corrected .
Do you know if there are typically any BIOS issues with this on 430TX boards or this something that tends to usually just work on any 430TX board ?

BIOS isn't really involved in RAM quantity on these boards.

Trying to figure out which board I confirmed this on back in the day (2002-ish), probably an Intel AN430TX.

dionb wrote on 2021-01-19, 21:10:

Not quite. […]
Show full quote

darry wrote on 2021-01-19, 20:45:

Sphere478 wrote on 2021-01-19, 20:34:

Hello :-) […]
Show full quote

Hello 😀

So I have a p55xb2 socket 7 motherboard with two sd ram slots and four simm ram slots.

I’ve previously been able to get 256mb into it and that’s about it.

What I understand is the chipset seems to only like 256mb

Obviously I could install 2 512mb sticks but those woupdn’t work and I have tried one with 16 chips per stick before and it did not.

My question is, if I install two sd sticks 256mb each with 16 chips each can I then install 4 128mb or 64mb simm sticks and end up with more than 256mb? Recognized? I know that when you install simms and dimms you sometimes get both to recognize but with the dimm being 1/4 the size.

I’m looking for any tricks to get above 256mb

I’m going to use a k6 III+ so my cachable limit is 4gb

The memory controller in the 430TX chipset is limited to 256MB RAM maximum, there is no workaround for that .

Not quite.

Intel's official specs give it max 256MB with 64Mb chips. But... the memory controller is identical to the i440EX's and can take 128Mb chips too. So with two double-sided 256MB DIMMs, you can do 512MB.

You do need to be pretty specific with the DIMMs and chips: 16 chips with 16Mx8 structure. Fortunately, pretty much any 256MB PC100 DIMM will have this. With PC133 you need to look out for 8 chip (256Mb per chip) modules, or worse 16 chip 32Mx4 things.

These are the sticks I have to play with so far.

All are chiped on both sides so assume double the chips that are visible.

I can get another double sided 256 if the ecc ones don’t work and the 256 plus the 128 works? Or is there a weird situation where 384 wouldn’t work as a test and 512 would?

The middle two are registered, they're not going to work on a non-server board. Desktop chipsets only eat unbuffered DIMMs. ECC or not is irrelevant.
Bottom one is iffy, for starters it's 128MB, and looking at the datasheets of those HYB39S64800CT-8 chips shows they can be configured either as 8Mx8 or 16Mx4. If the former, it will work, if the latter, it won't.
The top is the real deal - 16Mx8 chips, so 256MB usable by the i430TX.

Best case you can get 384MB with these DIMMs.

dionb wrote on 2021-01-19, 22:09:

The middle two are registered, they're not going to work on a non-server board. Desktop chipsets only eat unbuffered DIMMs. ECC […]
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The middle two are registered, they're not going to work on a non-server board. Desktop chipsets only eat unbuffered DIMMs. ECC or not is irrelevant.
Bottom one is iffy, for starters it's 128MB, and looking at the datasheets of those HYB39S64800CT-8 chips shows they can be configured either as 8Mx8 or 16Mx4. If the former, it will work, if the latter, it won't.
The top is the real deal - 16Mx8 chips, so 256MB usable by the i430TX.

Best case you can get 384MB with these DIMMs.

Sweet! When I get the board I’ll start playing with it.

Do you happen to have a twin to the 256 that I need?

dionb wrote on 2021-01-19, 21:37:

darry wrote on 2021-01-19, 21:24:

dionb wrote on 2021-01-19, 21:10:

Not quite.

Intel's official specs give it max 256MB with 64Mb chips. But... the memory controller is identical to the i440EX's and can take 128Mb chips too. So with two double-sided 256MB DIMMs, you can do 512MB.

You do need to be pretty specific with the DIMMs and chips: 16 chips with 16Mx8 structure. Fortunately, pretty much any 256MB PC100 DIMM will have this. With PC133 you need to look out for 8 chip (256Mb per chip) modules, or worse 16 chip 32Mx4 things.

Thank you, for that, I stand corrected .
Do you know if there are typically any BIOS issues with this on 430TX boards or this something that tends to usually just work on any 430TX board ?

BIOS isn't really involved in RAM quantity on these boards.

Trying to figure out which board I confirmed this on back in the day (2002-ish), probably an Intel AN430TX.

Thank you. The reason I mentioned BIOS is because of I know that at least some 440BX boards, for example, required BIOS updates to recognize 256MB DIMMs at full capacity (I am referring only to DIMMs that should be compatible, according to https://web.archive.org/web/20180103032407/ht … ram_bx_faq.html , but do not work due to BIOS limitations).

The documentation for BIOS Patcher 4.23 mentions BIOS limitations for 430TX and 440BX boards as well.
Excerpt from BIOS Patcher 4.23 (not clear if this functionality is implemented) :

1      Other things that are in progress now: - support of 64/128 Mbit memory on P1 platform (Via VPX and i430TX), 256 Mbit on P2/P3 platform (VIA 693A and some of VIA 694X)  

darry wrote on 2021-01-19, 22:48:

[...] […]
Show full quote

[...]

Thank you. The reason I mentioned BIOS is because of I know that at least some 440BX boards, for example, required BIOS updates to recognize 256MB DIMMs at full capacity (I am referring only to DIMMs that should be compatible, according to https://web.archive.org/web/20180103032407/ht … ram_bx_faq.html , but do not work due to BIOS limitations).

The documentation for BIOS Patcher 4.23 mentions BIOS limitations for 430TX and 440BX boards as well.
Excerpt from BIOS Patcher 4.23 (not clear if this functionality is implemented) :

Copy code to clipboard

1      Other things that are in progress now: - support of 64/128 Mbit memory on P1 platform (Via VPX and i430TX), 256 Mbit on P2/P3 platform (VIA 693A and some of VIA 694X)  

Surprised to see VPX and TX mentioned in same context - never heard of TX boards not eating 64Mb chips.

I think I have a TX board, iirc an MS-5158 knocking around somewhere. I definitely have DIMMs with 128Mb chips. If I can find the time (big if) I'll give it a spin to see if a random mid-range board does what I expect.

So does this bios patch apply to my board? How can I find out?

I’ve been able to get 256mb in it before but no more than that. Question is, is that because I didn’t try the correct parts?

The link you posted isn’t working

Sphere478 wrote on 2021-01-20, 00:32:

So does this bios patch apply to my board? How can I find out?

I’ve been able to get 256mb in it before but no more than that. Question is, is that because I didn’t try the correct parts?

Depends on the parts...

dionb wrote on 2021-01-20, 00:41:

Sphere478 wrote on 2021-01-20, 00:32:

So does this bios patch apply to my board? How can I find out?

I’ve been able to get 256mb in it before but no more than that. Question is, is that because I didn’t try the correct parts?

Depends on the parts...

Indeed. I don’t have any of those ram sticks any more but at least I know I have one 256mb stick that may be the right part.

dionb wrote on 2021-01-20, 00:20:

darry wrote on 2021-01-19, 22:48:

[...] […]
Show full quote

[...]

Thank you. The reason I mentioned BIOS is because of I know that at least some 440BX boards, for example, required BIOS updates to recognize 256MB DIMMs at full capacity (I am referring only to DIMMs that should be compatible, according to https://web.archive.org/web/20180103032407/ht … ram_bx_faq.html , but do not work due to BIOS limitations).

The documentation for BIOS Patcher 4.23 mentions BIOS limitations for 430TX and 440BX boards as well.
Excerpt from BIOS Patcher 4.23 (not clear if this functionality is implemented) :

Copy code to clipboard

1      Other things that are in progress now: - support of 64/128 Mbit memory on P1 platform (Via VPX and i430TX), 256 Mbit on P2/P3 platform (VIA 693A and some of VIA 694X)  

Surprised to see VPX and TX mentioned in same context - never heard of TX boards not eating 64Mb chips.

I think I have a TX board, iirc an MS-5158 knocking around somewhere. I definitely have DIMMs with 128Mb chips. If I can find the time (big if) I'll give it a spin to see if a random mid-range board does what I expect.

Hey, I learned that a 430TX could support 512MB, I likely never knew because I never looked into pushing one to its limits and I did not know anyone else who did . I played a lot more with 440BX boards, both mine and a few belonging to others .

I hope you get chance to test on one of your boards. If you do, and you have 512MB DIMMs, could you please test with those as well ? I wonder if they would be detected and work at half their nominal capacity, like they seem to do on a 440BX .

darry wrote on 2021-01-20, 00:47:

dionb wrote on 2021-01-20, 00:20:

darry wrote on 2021-01-19, 22:48:

[...] […]
Show full quote

[...]

Thank you. The reason I mentioned BIOS is because of I know that at least some 440BX boards, for example, required BIOS updates to recognize 256MB DIMMs at full capacity (I am referring only to DIMMs that should be compatible, according to https://web.archive.org/web/20180103032407/ht … ram_bx_faq.html , but do not work due to BIOS limitations).

The documentation for BIOS Patcher 4.23 mentions BIOS limitations for 430TX and 440BX boards as well.
Excerpt from BIOS Patcher 4.23 (not clear if this functionality is implemented) :

Copy code to clipboard

1      Other things that are in progress now: - support of 64/128 Mbit memory on P1 platform (Via VPX and i430TX), 256 Mbit on P2/P3 platform (VIA 693A and some of VIA 694X)  

Surprised to see VPX and TX mentioned in same context - never heard of TX boards not eating 64Mb chips.

I think I have a TX board, iirc an MS-5158 knocking around somewhere. I definitely have DIMMs with 128Mb chips. If I can find the time (big if) I'll give it a spin to see if a random mid-range board does what I expect.

Hey, I learned that a 430TX could support 512MB, I likely never knew because I never looked into pushing one to its limits and I did not know anyone else who did . I played a lot more with 440BX boards, both mine and a few belonging to others .

I hope you get chance to test on one of your boards. If you do, and you have 512MB DIMMs, could you please test with those as well ? I wonder if they would be detected and work at half their nominal capacity, like they seem to do on a 440BX .

I tried what I believe to be a 16 chip 512mb stick in this board 16 years ago and It did not work. I don’t remember if it was a no post or only showed 64 or 128mb. Or something like that. I want to say no post.

But I may be getting two 512s to try soon. It would be great if they worked but I don’t think they will

I was thinking of ordering some 128mb simms for this also maybe some 64mb ones.

Anything I should look for? Anything that would stand a better chance of working?

Are we pretty much consigned to “using simms and dimms together” as not being a tool for cramming more ram in there?

The link I posted shows all your options.

https://stason.org/TULARC/pc/motherboards/Q/Q … ium-P55XB2.html

You can use banks 1+2, 1+4, 2+3 or 2+4 together, but not 1+3 or 2+4. So 1+2 or 3+4 is your best bet, depending which is faster. And 256 MB total is your limit.

I was sure that 256 was the limit, but I decided to try for myself. Starting with a 256 PC133 in one slot that I've been using for some time, trying any of the other 256 meg sticks of SDRAM I have in slot 2 would just cause it to beep without posting. But there were a couple of different 128s that it recognized and would POST with, recognizing 384 (393216)! But in both cases, it will only boot up in Safe Mode, and I've been content with the performance of this machine with 256 megabytes so that's the end of the experiment for me.

Asus TXP4 with a K6-3+.

Repo Man11 wrote on 2021-01-20, 03:35:

I was sure that 256 was the limit, but I decided to try for myself. Starting with a 256 PC133 in one slot that I've been using for some time, trying any of the other 256 meg sticks of SDRAM I have in slot 2 would just cause it to beep without posting. But there were a couple of different 128s that it recognized and would POST with, recognizing 384 (393216)! But in both cases, it will only boot up in Safe Mode, and I've been content with the performance of this machine with 256 megabytes so that's the end of the experiment for me.

Holy crap! It worked!

Any ideas about why safe mode was required? Can you post pics, details of the sticks that worked for you and did not?

Sounds like there is definitely hope!

What cpu are you using? Also is motherboard cache enabled?

I’m really hoping that my motherboard arrives tomorrow.