Thinkpad 600E not accepting 256Meg PC133Memory

[tilhasbb]

Hello,

I have a Thinkpad 600E Type 2645 laptop (PII 366 using 440 chipset).
I was unable to find any 256 Megs PC100 or PC66. I've read that the laptop does not like PC133, high density memory, CL3.

I purchased a Samsung 256Meg PC133 (K4S561632E-UC75)Sodimm memory. I am unable to get the laptop to detect it.

The memory alone will not get detected but the BIOS shows it detects it but is not in usable. I've tried to disable the onboard memory from the bios hex editor and that didnt help....

Any ideas?

[rkawakami]

Welcome to thinkpads.com!

The part number you have given refers to the individual memory IC that's on the board (as far as I can tell). The datasheet for it indicates that the refresh spec is 8K cycles, which is another way of saying it is "high density". Therefore, your 600E is acting correctly and will not be able to use it. You need to find/use a 256MB memory module that has 16 chips on it (8 per side) as this is the general description which refers to a "low density" module. The IBM FRU is 33L3069 or 33L3070.

[tilhasbb]

Thanks rkawakami.
You are correct, that # is for an individual memory IC and it has 4 chips on each side. The Ebayer told me it was low density...

Wouldn't the laptop atleast use half of the chip?
Since the laptop detects the memory but puts it as unusable can't I override the bios?

[rkawakami]

No, the 600-series systems use a memory controller which requires the use of 4K refresh devices, aka "low density" parts. I don't know of any way that you could tell / configure the BIOS to consistently and safely ignore half of the memory. While the system was designed to use low density PC100 modules, you can also use PC133, again, as long as there are 16 chips (total) on the module. You should politely ask for a refund and tell the eBay seller that he/she is mistaken and that "low density" does not equate to the lesser amount of chips on the module (i.e., 8 vs. 16). The term "low density" is actually talking about the memory size of the individual chips used to make up the module. In the case of a 256MB module, "low density" means sixteen 16MB devices. "High density" is eight 32MB memory chips. Thus, "low" equals 16MB and "high" means 32MB. The real difference however is the number of refresh cycles that are needed to keep the memory "alive". The 16MB devices (and the memory controller in the 600) requres 4,096 cycles (4K), while the 32MB devices need 8,192 (8K).

[tilhasbb]

rkawakami> Thanks for the explaination.

[tilhasbb]

If i find a 256 Meg Low Density Module. Can i use it with a low density 64meg. To have a total of 256+64+32= 352Megs?

[rkawakami]

Yes, that should work. The 600E can take up to 544MB (2 x 256MB + 32MB onboard). As long as each SODIMM is of the low density variety (and obviously, defect-free), then you can mix different sizes. If you do not already have a memory diagnostic program, I highly recommend that you use something like this:

http://www.memtest.org/#downiso

Available either in a floppy boot disk or CD image, memtest86+ will fully check your memory modules. Boot the system using the floppy or CD and let the program run for at least three complete passes. Any errors that are found will be displayed (in red) on the screen. If you have never run any memory diagnostic before, I would suggest that you remove all modules from the 600E and test the built-in 32MB first. Then add in one module and re-run the diagnostic. If it passes, take that module out and put in your other one. Run memtest86+ again. If the second one passes, then install both and run memtest86+ a final time. This might seem like overkill, but it's the easiest way to determine which module is defective (any errors found should be due to the memory installed last).

edit: Now that I think of it, some 600E systems may be problematic when it comes to the maximum memory allowed. What's the TYPE number of your system (2645-xxx) and the BIOS revision level?

[tilhasbb]

2645-4AU
I can't find the bios info.... where would I look?

[rkawakami]

Revision information should be available on one of the BIOS (Easy-Setup) screens. I don't have a 600E with me right now, but I believe that it will be on the first screen. Hold the F1 key down while turning the system on and continue holding it until you get the green-on-black screen. BIOS revision is probably something like INET28WW. That's what my 2645-4AU has in it according to my notes and that version is several back from the latest one. I've got 2 x 256MB low density modules in that system and it registers 544MB. So as long as your system has 28WW or newer, you should be okay.

edit: Here's a previous post on the subject: http://forum.thinkpads.com/viewtopic.ph ... 986#240986

[cure]

Does low density PC133 work?

Thanx.

[u.mac]

Does low density PC133 work?

Low density PC133 shall be compatible to PC100 + PC66... but some low cost modules may be not.

[cure]

Does low density PC133 work?

Low density PC133 shall be compatible to PC100 + PC66... but some low cost modules may be not.

Can you or anyone else please clarify this further as the answer, while helpful, is also frustratingly vague.

[u.mac]

Low density PC133 shall be compatible to PC100 + PC66... but some low cost modules may be not.

Can you or anyone else please clarify this further as the answer, while helpful, is also frustratingly vague.

Take a look... http://www.dewassoc.com/performance/mem ... _valid.pdf
But some manufactors ignores the 'Intel Validation Specification" - so no all PC133 low density modules will work at FSB66 or 100.

Kingston builds today an incompatible PC133 module... under same buildnumber they build ~2005 compatible RAM... so it's like roulette to find the right one...