Laptop sees 64meg memory module as 192meg?!

[JEDI]

it's a 64meg mem module. alone, it sees it as 64meg.

but when i add a 2nd memory module, it sees it as 192meg and give me a total of 256megs. this is reported in bios.

it doesnt matter which memory slot i put the module in.

the reason why i know it's this module that is being seen as 192meg and not the other one is that CPUID says the mem slot contains 192meg memory.

since bios reports total memory as 256megs, WinXP thinks it has 256megs (instead of 128megs).

Why does the laptop see the 64meg module as 192megs???

THX!

 

[MrControversial]

Maybe it's not a 64MB module?

 

[LTC8K6]

Does the laptop have any on board memory? If it has 128 on board, that could account for this behavior.

 

[Tarrant64]

Yes, if it has onboard memory then that's why it will 'appear' to be off.

 

[JEDI]

what do you mean off?

no, i don't think it has onboad mem.

why would it say 64meg with only 1 64meg module, but 256megs when i add a 2nd 64meg module?

 

[ViRGE]

Originally posted by: JEDI
what do you mean off?

no, i don't think it has onboad mem.

why would it say 64meg with only 1 64meg module, but 256megs when i add a 2nd 64meg module?

I've had old Gateway Solos report a 64MB module at 21MB before(and no, it didn't use shared memory for video), so at this point I'd consider anything possible. Run MemTest86, and if it doesn't screw up, consider yourself lucky.

 

[JEDI]

took out both mem modules. laptop does not boot, thus i'm assuming there is no built in mem.

i ran memtest. it saw a combined 256megs. all tests past.

but how is that possible when i only have 128megs in the machine???

i know it;s 128 because it's doubtful that mem modules come in 192meg flavors.

 

[AMDZen]

What motherboard? Does it have the newest BIOS installed?

 

[JEDI]

cpuid says the laptop is using abitII chipset?

yes, latest bios is installed

 

[ohnnyj]

What about shared video memory?

 

[JEDI]

ati video..8megs of dedicated memory..nothing shared

dont get me wrong, the laptop is running fine. no blue screens... yet

since it past memtest, does that mean i really have 256megs of mem and not 128?!

 

[ohnnyj]

Well how well does it run?

 

[JEDI]

not well. slow bootup, lots of disk swapping.

thats why i think it's only 128megs.

 

[ohnnyj]

Who is the manufacturer of your laptop? You could try updating to a more recent BIOS if you have not done so already.

 

[VirtualLarry]

Wow, interesting scenario.

Are you certain that the 2nd module isn't really a 256MB module? I don't see any mention of testing just that one installed alone. Perhaps the chipset will only handle 256MB and the 64MB module also installed simply gets ignored?

The other possibility, is that the BIOS is somehow improperly programming the memory-controller of the chipset, such that a portion of the DRAM array is actually "shadowed" at two different ranges of physical addresses as seen by the CPU. (Is that even possible with a PC chipset's memory-controller? I know that it is often done in things like consoles and arcade games, mapping the same DRAM to multiple address ranges. I've never seen that ever happen on a PC, personally, unless you count a video card's mapping of the first 128KB of video ram (A0000-BFFFF) as well as the LFB address (D0000000-D07FFFFFF), etc.)

If the second were true, then memtest86 would likely not detect that, since it would have to be designed specifically to do so. That would be a rather extraordinarily rare case, though, and would likely be due to a BIOS programming error in detecting the installed DRAM and initializing the memory-controller. So the first reason is far more likely, IMHO.

 

[JEDI]

from the topic summary:
Dell Latitude CPx (p3-500) w/latest Bios

when i have either 64meg memory module in, the laptop reads it as 64megs. when i put both in, the laptop sees it as 256megs in bios. winxp using bios to determine the memory, so it also reports it as 256megs.

yes it is damn strange. and the laptop warrenty expired YEARS ago so no tech support.

i just started using this laptop again this year after over 2 years of collecting dust. it was giving me random blue screens under Win2k back then, but i format/installed WinXP and nothing bad has happened so far.

 

[ohnnyj]

Well if you had 64 to begin with, bought another 64 and it shows as 256 but runs like 128 I would say it is 128 w/an incorrect report of more. With a laptop running XP w/256 of RAM and a P3 500 I think this is the most logical explanation.

 

[VirtualLarry]

Does this laptop have a CD drive? What about using a bootable Knoppix "liveCD" Linux distro, I hear there are some for doing diagnostics. See what it reports as far as installed memory, although I have a feeling that it probably gets that info from the BIOS too, during the bootloader stage.

What does Everest report, in terms of reading the SPD and DMI data for each of the DIMMs and DIMM slots, respectively? That might give you more info, at the very least. Are both of the DIMMs absolutely visually identical? Or are they different? Perhaps post the various chip codes, in case one is in fact a 256MB and the other a 64MB.

 

[JEDI]

Originally posted by: VirtualLarry
Does this laptop have a CD drive? What about using a bootable Knoppix "liveCD" Linux distro, I hear there are some for doing diagnostics. See what it reports as far as installed memory, although I have a feeling that it probably gets that info from the BIOS too, during the bootloader stage.

What does Everest report, in terms of reading the SPD and DMI data for each of the DIMMs and DIMM slots, respectively? That might give you more info, at the very least. Are both of the DIMMs absolutely visually identical? Or are they different? Perhaps post the various chip codes, in case one is in fact a 256MB and the other a 64MB.

what is everest?

both mem modules are different.

this is an old laptop. neither mem module says how big it is. it just has codes on the chips itself.

64/192meg module is a compaq brand and a label on it says: mt8lsdt864hg-10ec5
other 64 meg module is a toshiba brand: 454935/0028ukc, 24m x 64

the '24m x 64' means 64meg?

 

[TheInvincibleMustard]

The MT8LSDT864HG-10E module you've got listed there is indeed a 64MB SODIMM, chips come from Micron
http://www.micron.com/products/modules/sdram/part.aspx?part=MT8LSDT864HG-10E

The other one, are you sure it's using Toshiba chips? Generally Toshiba RAM start with TC ... Is that the only markings on the stick anywhere? And I would hazard a guess that the second stick is actually a 192MB stick, due to the 24m x 64 markings -- 24*64=1536 ... 1536/8=192 (eight bits to the byte), and that's where the confusion is coming from.

 

[VirtualLarry]

Originally posted by: JEDI

Originally posted by: VirtualLarry
What does Everest report, in terms of reading the SPD and DMI data for each of the DIMMs and DIMM slots, respectively?

what is everest?

Everest home page
1.51 download (MajorGeeks)
screenshot (note carefully the DMI and SPD options on the left-side menu)

Originally posted by: JEDI
both mem modules are different. this is an old laptop. neither mem module says how big it is. it just has codes on the chips itself.
64/192meg module is a compaq brand and a label on it says: mt8lsdt864hg-10ec5
other 64 meg module is a toshiba brand: 454935/0028ukc, 24m x 64
the '24m x 64' means 64meg?

The first part of that code found this page, which seems to indicate that it is a 64MB SO-DIMM.
Second one, couldn't find anything conclusive. The 24m x 64 is rather... strange. Generally they are listed as 2/4/8/16/64M x 64 (or x72, in case of parity/ECC DIMMs). Bizarrely, I think 24M x 64 would in fact be 192MB. Does it show up as that size when installed by itself, in either slot?

I've never, ever, seen a non power-of-two sized memory stick though, that would rather be a first. It would likely have to have an un-even amount of chips, or chips of non-matching sizes, on each side. Are the numbers/branding on the chips themselves, different between the two sides, on either DIMM?

Hopefully Everest will turn up some more info on this, and show the true size of the DIMMs from the SPD info.

Edit: link , link . Apparently, 192MB SO-DIMMs do exist, specifically as an add-on for notebooks that have 64MB of RAM (permanently) pre-installed. How unusual. Never seen anything like that in the desktop realm. I don't have nearly as extensive experience with laptops. Looks like I learned something today.

PS. TheInvincibleMustard beat me with his reply.

 

[TerryMathews]

Originally posted by: VirtualLarry
I've never, ever, seen a non power-of-two sized memory stick though, that would rather be a first. It would likely have to have an un-even amount of chips, or chips of non-matching sizes, on each side. Are the numbers/branding on the chips themselves, different between the two sides, on either DIMM?

I have. You've got to remember, DIMMs are logically (electrically) two SIMMs - banks 0 and 1. A 192MB DIMM would be one bank of 128MB and one bank of 64MB. Chips wouldn't have to be uneven either. 6 32MB chips would do it. My guess would be that looking at the SODIMM, either there are 4 chips on top and 2 on bottom, or 6 on top and nothing on bottom. I've personally seen a 6 chip SODIMM before, it was designed for a PowerBook G3. A little bit taller than a normal SODIMM, kinda like the old super-large SDRAM DIMMs where they were twice the height of a normal DIMM.

 

[imported_Hi]

Originally posted by: JEDI
it's a 64meg mem module. alone, it sees it as 64meg.

but when i add a 2nd memory module, it sees it as 192meg and give me a total of 256megs. this is reported in bios.

it doesnt matter which memory slot i put the module in.

the reason why i know it's this module that is being seen as 192meg and not the other one is that CPUID says the mem slot contains 192meg memory.

since bios reports total memory as 256megs, WinXP thinks it has 256megs (instead of 128megs).

Why does the laptop see the 64meg module as 192megs???

THX!

why do you care so much its not like its less then spec