Using 64Mbit DRAM in old boards.

Is your memory not fully recognized? (Intel VX chipset Memory recognition)
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NickS
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Now that 32MB 16-chip DIMMs are costing >45 Euros, is it feasible to use a 128MB 16-chip DIMM costing ~20 Euros instead i.e. does it matter that 3/4 of the DIMM is not used ? Has anyone tried this ?
ajzchips
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I was at the shop of a friend of mine yesterday. A guy bought 3 128MB DIMMs (PC133) for an old mobo that would only see 64MB per DIMM.
The system worked perfectly fine with only 192MB (instead of the full 384MB).
So the answer would be: it should work ok; only some address lines won't be used.
apple_rom
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>Has anyone tried this ?
256Mbx2 on i430VX as 64Mbx2=128Mb work more than year.
By the way, I already have solved this problem (support 64/128Mbit devices) for mobos on VIA VPX (and "higher") chipset with not support 64/128Mbit devices in BIOS (see only 1/4 RAM).
Wimsbios has NOT tested apple_rom's BIOS patching techniques. USE AT YOUR OWN RISK!
Rainbow
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I have two PC Chips M520 i430VX boards. Tried with 64MB, 128MB and 256MB DIMMs - it never worked :(
Patched and tested BIOSes are at http://wims.rainbow-software.org
UniFlash - Flash anything anywhere
edwin
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Were you able to get any SDRAM working in them at all?
edwin/evasive

Do not assume anything

System error, strike any user to continue...
Rainbow
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Don't have any other SDRAM...
Patched and tested BIOSes are at http://wims.rainbow-software.org
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NickS
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@rainbow: Is there any option to disable configuration by SPD ? Did you try that ?
Rainbow
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i430VX chipset does not support SPD (and SMBus) at all.
Patched and tested BIOSes are at http://wims.rainbow-software.org
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NickS
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@rainbow: In that case I wonder why it doesn't just ignore the extra address lines and work....but to agree with you, I've seen 32MB 8-chip completely ignored on an ICL i430VX motherboard, 32MB 16-chip works OK (max two modules).
Rainbow
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Maybe it needs two-sided module to work?
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Denniss
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I have some single sided 16MB ones working on i430VX - seems I have to test 128MB single-sided 8chip
I have some VX-Boards to test with if you're interested in
edwin
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I have a doudle-sided 128MB module lying around and some i430VX boards. If I can find the time...
edwin/evasive

Do not assume anything

System error, strike any user to continue...
KachiWachi
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Intel says (from the VX design guide, 297469.pdf) -

"DRAM Interface—The DRAM interface is a 64-bit data path that supports Standard Page Mode (SPM), Extended Data Out (EDO), and Synchronous DRAM (SDRAM) memory. The DRAM interface supports 4 Mbytes to 128 Mbytes of system memory with five RAS lines and also supports symmetrical and asymmetrical addressing for 512Kx32, 1Mx32, 2Mx32, and 4Mx32 deep SIMM modules (single- and double-sided). The TVX supports SDRAM 1Mx64, 2Mx64, and 4Mx64 deep DIMM modules (asymmetrical single-and double-sided). The 430VX requires that x32 and x64 SIMMs/DIMMs be used."

"SDRAM—Refer to the latest Unbuffered Standard/SDRAM DIMM specification for the latest DIMM connector pinout. In addition, (1) The 82430VX supports unbuffered DIMM modules only. (2) Each DIMM requires two separate HCLKs to support double sided DIMMs. (3) Generally, only SDRAM and EDO come on DIMM’s, however, the DIMM spec also specifies FPM. To support EDO/FPM on the same DIMM, OE0# (pin 31) and OE2# (pin 44) on the DIMM connector must be connected to ground on the motherboard, and WE2# (pin 48) must be connected to one of the TVX’s Memory write enable signals (WEA# or WEB#). (4) Most SDRAM will be 3V only (i.e SDRAM I/O pins will not be 5V tolerant). When mixing and matching SDRAM with EDO/FPM, the EDO/FPM should also be 3V (i.e. receive and drive 3V levels)."

Also from Intel here...

"Do 430VX chipsets work with 4M x4 SDRAMs?

430VX does not support x4 SDRAM configuration.

The SDRAMs, due to their synchronous nature, put extra pressure on meeting timing specifications. Specifically at 66MHz (15ns clock period), the clock skew and Hclk signal integrity become major issues. Consequently, it is purely a loading/timing reason why we cannot support x4 SDRAMs. We do support x8 or x16 SDRAMs because now loading is halved. Future chipsets are heading for higher speeds and will be even harder to meet the timings. In summary, 430VX can drive 8 loads per row. This sets our lower limit at x8."
apple_rom
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>I have two PC Chips M520 i430VX boards. Tried with 64MB, 128MB and 256MB DIMMs - it never worked
In this case - it`s only BIOS-problem (Memory_Detect subroutine in BootBlock).
i430VX can work with most 8chip/SingleSide or 16chip/DoubleSide memory modules. For 64Mb and higher (64/128Mbit technology) - size will divide by 4 but must work correctly. (if you find 32chip/2side 64Mb DIMM - size will be see "full").
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