Ram-Identification-Tool

[europanorama]

i need a tool which can precise tell me how the chips on sdrams are organized. by this way i can understand if they match the mb-specifications.

unfortunately on intel-site latest data is from 1998 or 99.

btw: i had a suwin-error at 65% of a win-setup(winme). i am sure it was the additional pc-133-64mb-stick. the others are pc-100 and the manual urges them not pc-133. they are running together but setup is delicate enough to refuse the mix.

[Peter M]

Speed grade too fast? Doesn't matter, SDRAM does not have an operating lower limit on the clock rate. Anyone telling you otherwise is talking bull****.

SDRAMs cannot be identified in software; that's why every DIMM has a describing "SPD" EEPROM on. All you can do is read that out - but such a software is chipset and even mainboard dependent.

All you can do is read the fine print on the chips - physically - and then visit its maker's web page to find out what it is.

For memory TEST, www.memtest86.com

[europanorama]

ok.

i have tried to understand the sdram-dimm-configurations-tables on intel-site without great success.

i am unable to understand the relationship between
1. dimm capacity
2. dimm organization
3. sdram density
4. sdram organization
5. no of sdrams
6. no rows of sdram
7. no banks in sdram
which of the am points can be identified physically?


if i would i could go to the shop and ask for the appropriate dimms.

i will retry understanding this article:
http://www.arstechnica.com/paedia/r/ram_id-1.html

who knows other links?

[Peter M]

Once you know what the SDRAM parts are (3,4,7 in your list), there is just one way to make a DIMM rank from it (1,2,5 are then given). 6, rows, you probably mean ranks - DIMMs have either one or two of them (single or double sided, although there are exceptions).

The starting point is knowing the SDRAM chips' properties.

That article is way outdated, I'd say nevermind it.

[europanorama]

i am exactly writing down how the tables are listed.

its really strange that intel is not interesting informing the public about such important issues. it is really outdated 1998 or 99.
that means i cannot find the newer 4chips/side-sdrams.

thats exactly what i need to know. which number is related to the amount of chips?
eg.
256mb
32mx64-dimm organization
128 mbit-sdram density
16mx8-sdram organization
16-no of sdram
2-no rows of sdram
4-no banks in sdram

[Peter M]

It means you got a 256-MByte DIMM there, 64 bits wide (read: non-ECC, else you'd have 72 bits).

The SDRAM chips are 128 Mbit technology, geometry is "16Mx8", will say, each chip delivers 16 million data sets, each 8 bits wide.

SDRAM technology from 64 Mbits upward always has 4 internal banks.

Now with 8 bit wide devices, you need eight to achieve 64-bit total width. And with 128 Mbits per chip, that'll be 128 MBytes per complete set aka DIMM side aka rank aka (incorrectly, see below) row. So obviously you'll need two ranks to get to 256 MBytes with that kind of SDRAM chip.

But the really important stuff when it comes to chipset compatibility is in the SDRAM chip's geometry. If you look at a "16x8" chip's datasheet, you'll discover that these use (2) bank and (12) row select lines, and have (10) column selects. Now since banks and rows are selected in the same cycle, your chipset needs to have (14) memory address lines. The 10 column address lines means that one page is 2^10 datasets, or 8 KByte, so your chipset needs to support 8K pages.

See, it's complicated. Nothing that would make any sense in a user's manual ...

Let's cut it short.Being a BIOS engineer, I know a bit about this What chipset do you have there? I'll tell you what it's capable of.

[europanorama]

sorry i did not post the last row of sdram-information(unbuffered dimm specification from intel-site)

no address bits
row/bank/col
12/2/10
as you told

the four pcs in questions are.(chipsets)
1. ali m 1541 a1 -pentium 166mmx ga-5aa
2. via ...c598mvp -pentium 200mmx-hot 597
3. via ..c693 - pentium 3-dfi-pa61-rev2
4. intel 810 L-cpu -celeron- dfi-cw 36-L

3 and 4 do not count up the newer pc-133-256 double-side 2x4 chips.
for no 2 i will have to recheck, machines are running at the moment. no 1 is taking all dimms i have.
all pcs ask for pc-100-sdram!

pa-61 rev 2 says in the bios-update-section:

to also enhance the support of ibm 256 mb pc-133 dimm module(0325804ct3a 75a need hardware modification(does this mean bios-update?)
only dimm1 and 2 support 256 mb, dimm3 only 128mb due to limits of northbridge

[Peter M]

ALi 1541 aka Aladdin V can at least do the 12/2/10, if not the 13/2/10. You seem to indicate it can - wouldn't be a surprise since its predecessor 1531 aka Aladdin IV could do 12/2/10 already.

VIA 598 aka MVP3 and Intel 810 both max out at 12/2/10 for sure.

VIA 596B is a southbridge. Please try again You are looking for a 691, 692, 693, 693A, 694X or Z, 8601/A/T, or 8604 here.

On a four-chips-per-side, eight total, 256-MByte DIMM, as you certainly can figure out yourself now, you cannot have anything but 16 bits wide 256-Mbit "16Mx16" SDRAM devices. Now the nasty surprise is that these are NOT 12/2/10 ... all 256-Mbit SDRAMs are 13/2/x, the 16 bit wide ones are 13/2/9.
So the older chipsets with only 14 memory address lines see only half of them.

[europanorama]

i have made an update in first message, i will now try the module in pc 2(via mvp3)

[Peter M]

MVP3 no can do. That's for sure.

Neither can 693, if I remember correctly. 693A can run 13/2/x RAMs in the first two DIMM slots _if_ the mainboard makes the connection for the MA14 line. (That's probably what's meant with "hardware modification", it seems only later board revisions have that right.)

[europanorama]

1. please remember that the mentioned 256mb is from the intel-list.
i have a different one. 2x4(4 chips on each side)
only ali m1542 can read it fully.

[Peter M]

That's what I'm saying. The one described will work in any of your boards; the one you have will work on the ALi and might work on the VIA P-III board, while it won't work on the other two.

[europanorama]

that is exactly what i do not understand: mine(2x4) is working on all my three boards plus the fourths iof my customer. but on my pIII via-board it is counting up only 50%.. maybe i must make bios-changes. its a no-name-memory. pc-133

[Peter M]

There is a remote chance that even though it populates both sides, it is actually a single-rank DIMM using 12/2/10 x8 devices, not two ranks 13/2/9 x16.

What chips are on it, then?

The PIII board might use a BIOS update, yes.

[europanorama]

ok, the mem is running on the actual machine. i will identifiy and post later this evening.

dfi pa-61-rev d2-board shows pcb revision d2(which seem to be the latest d2-bios-update. this was done.

but there is a newer rev d. i dont know if i can use it. its one month younger, 2000/8/18
seagate 32040A hdd under win2k(sometime unknown hard error)

if i have a list if bios-updates i will usually use the latest one, right? leave the older one beside?

i have described the 256/256/128 limits due to the northbridge
693-limits. btw: the board is asking for pc-100, but i use pc-133

the main problem is: i cannot use the cheaper sdrams. 256 cost 110 chf, cheaper ones 44 chf or 55( usd=1.5x chf)
i sell used pcs. thats why ne pentium 4-ddr could be better investments for customers.