# Thinkpad 600 Memory Upgrade Problem



## DRHamp (Aug 4, 2005)

I recently bought an IBM Thinkpad 600 off of EBay. It is running Windows 2000 Prof. It came with 96MB of RAM consisting of 32MB base RAM and a 64MB SODIMM stick. I wanted to upgrade it to max memory which according to the IBM docs, is 288MB using 2 128MB SODIMMs.

I bought a pair of 128's off of EBay (new Kingston) and installed it. So, here's the problem

The machine only shows 228MB of RAM. RAM diagnostics show no problems. 

Just to be sure that I didn't get a bad stick -- I ordered two more 128 sticks from a different vendor. Installed it today --- machine still shows 228 MB.

Any ideas anyone ? :4-dontkno


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## Xingbot (Aug 3, 2005)

Well, the two 128s only add up to 256.... You'll need two 144 mb sticks to get the 288mb total. Don't know where you'd find 144mb sodimms, though several companies do seem to make 144mb rambus sticks. As to why its only showing 228 instead of 256, the graphics chip is probably integrated and uses part of the system memory.


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## DRHamp (Aug 4, 2005)

Thanks for the response.

There is a base 32MB on the board, then 2 additional 144 pin SODIMMs can be added. The two 128MBs plus the 32MB give you 288. That is according to the IBM Docs.

It's been suggested on another forum that I try to run down some PC-66 RAM and not use PC-100. If I can find it, I'll give that a try.


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## tedscales (Aug 16, 2005)

I have the same problem, and from what I can see you are stuck with it.

The following is based on information gleaned from running the Mainboard Information module in SiSoft Sandra, available at various download sites.

The Thinkpad 600 has four memory banks. The on-board 32 MB uses bank 0. You can disable this memory but it doesn't make the bank available.

It seems that some add-in memory is laid out 64 megs per bank, other memory is 128 megs per bank.

If you have 64 MB modules there is no problem.

If you have an unsuitable 128 MB module this will work as 128 MB when it is in the rear slot used by banks 1 and 3, but the front slot only has bank 2 (bank 0 already taken as stated above) so only 64 MB will be accessed.

You should see this effect by only using one of your 128 MB modules. In the slot closest to the back of the computer you'll have 128 + 32 = 160 MB, in the other you'll get 64 + 32 = 96 MB. When you add the second module you'll get 128 + 64 + 32 = 224 MB.

If both memory modules are in, try holding down F1 key when you power up to bring up the Easy Menu, and click the little bird on Config. Then click on memory, and you should see Installed Memory: 294912 KB, Usable Memory: 228992 KB. So the hardware can see the memory, it just won't use it.

I have two machines with two Kingston KTC-A1700/128 modules and a Toshiba PC100-222-620 which all behave as above. I also have a Crucial MT8LSDT1664HG-662E2. When I put the Crucial in either slot of either machine it shows up as 128 MB in bank 1 (rear) or 2(front). If it goes in the front, banks 1 and 3 are available in the rear slot to let the Kingston or Toshiba module access as 2 64 MB banks, total 32 + 128 + 128 = 288. If I swap the modules I'm back to 224.

So you have three options.
1: live with 224 MB
2: get a Crucial module and put it in the rear slot
3: find another brand that will access as a single bank
4: find out why the Kingston modules access as two banks and work out how to do something about it.

I've been pursuing 4. and 5. at a slow pace, and will report any findings. It does seem to be speed related as the Crucial memory is 66 MHz while the other two are 100 MHz. Unfortunately there seems to be no BIOS setting to alter the memory parameters.


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## ebackhus (Apr 21, 2005)

I had a 770 some time ago and it also had the 32MB built in. It maxed at 256 and that was with 2x128MB sticks installed. The onboard was disabled if that was the case. The bus speed is 66Mhz in the 600 series so you'll either need RAM that can clock back or true PC66 modules.


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## leroys1000 (Aug 16, 2005)

You also need to accout for system memory that is allocated for
onboard video.
That is probably where you are losing it.


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## tedscales (Aug 16, 2005)

As this problem seems to be widespread, it would be helpful to get feedback from other Thinkpad 600 owners (600e and 600x machines seem to handle memory differently, but if you have info, please post it).

Could you please let us know, where possible:
model of thinkpad (600, 600e, 600x) and type number (2645-xxx);
the brand, capacity and part number of your memory module(s);
for each module, its capacity reported in both front and rear slots;
which bank(s) it uses if you can run SiSoft Sandra or some other reporting software;
whether you know of any other cases where people have these machines, or any references to the problem on other web sites or elsewhere.

It would be nice to collect enough information to track down the problem, or at least work out which modules can be used to get the maximum 288 MB.


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## ebackhus (Apr 21, 2005)

I believe that the video system has 1-2MB of dedicated RAM on the video daughterboard.


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## SnakeEyes (Aug 26, 2005)

I too just ran into the same problem. I have a 600 2645-31U. I bought PC66, 16x64, P/N SD144SO128 to add to my other ram of similiar specs. Sure enough only finds 224. Even swapped the modules from front-back before posting here. How do I find out what it's reporting for each bank?


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## SnakeEyes (Aug 26, 2005)

OK I may have solved my problem, seems doing a little searching to make sure (been awhile since I bought the old 128mb) it seems it may be a 133mhz.


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## SnakeEyes (Aug 26, 2005)

Ok, that didn't work. I just installed two PC66 128MB chips and it still only shows 224. Any suggestions what's going on and how to fix it?


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## redlineteck (Sep 3, 2005)

*IBM 600 Laptop Display Problem*

I have the same problem with two IBM 600. The LCD screens will not display anything. If i plug in a CRT external monitor they display fine and go through the boot up process fine. I know the LCDs work because i have yet another 600 that they work on fine. Any ideas?


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## kurra_t (Oct 13, 2004)

Hey i have a question regarding upgrade. How actually did u upgrade. did u upgrade it or got someone to upgrade RAM. I mean to ask how can I upgrade my laptop( Sony VAIO VGN-FS630/W) . i want a 512 MB ram installed. CAn i do it on my own do i need an expert for that. Please help me
thanks for any input


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## SnakeEyes (Aug 26, 2005)

How about starting a seperate thread since this is about a specific issue with the Thinkpad 600 and you have a different laptop?


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## kurra_t (Oct 13, 2004)

sure and thanks for ur suggestion


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## StoneLion (Aug 30, 2006)

*Instructions for dissabling the onboard 32mb*

Could someone please provide detailed instructions for disabling the onboard 32mb memory on the Thinkpad 600. I have seen in many places that it can be done, but I am unable to find out how. My laptop is the Thinkpad 600 2645-45u.


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## laboye (Apr 11, 2006)

The 600 series has 2MB dedicated video memory via a Neomagic MagicGraph128XD video controller. The 600 series BIOS also does not permit the disabling of the onboard RAM. I used to own a 600E and it never exhibited this problem. I was able to upgrade it to the full 288MB. Be sure you use the proper type of RAM, or it will disable certain areas just to work. tedscales's bank explanation is true. Unfortunately, there is no way to disable that onboard RAM. Somehow the disabled built-in RAM on your machine is cascading over the 256. Try one module at a time and report the detected usable RAM for each.


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## StoneLion (Aug 30, 2006)

I regret to inform you that you are wrong. You can in fact disable the onboard memory. I discovered how. within the bios, go to the config menu. pres ctrl-d. this will bring up a hex editor for the bios. within the base 128 bios go to hex address 2b, that byte must be edited such that the first bit is enabled. it appears that 80 is the common setting for this byte (which controls all the memory banks on the laptop. by setting this byte to 81 you can disable the bank that holds the onboard 32mb. (Be careful how you modify this area, if you screw things up, you won't be happy.) When the byte is edited, press F2 to save to the cmos, then exit the editor and shutdown the machine. (without exiting the bios setup). I believe you need to do it this was because if you exit the bios, it will save its settings overtop of the one you just changed, possibly undoing your work. When the machine started up again, I did see that the 32mb onboard was disabled, however, the memory in the second bank was still cut in half (my original problem involved the typical setup of 2 128 mb chips with the 32mb onboard showing up as 224mb). After disabling the 32mb onboard, the 2 128mb chips I have installed were used as 192mb total (the scond chip is still only used half way). Within the advanced diagnostic section of the bios (Go to the test menu and pres ctrl-a), i did notice that the bios does infact notice that chip as a 128mb module. this would be because it simply reads the eeprom on the module and knows the correct size of the chip. So here is where I start to conjecture the many POSSIBLE reasons for the reduction in usable memory. I believe that it could be that the laptop is un able to address all 128mb of that bank (meaning the chip requires a dual bank socket). I believe that the memory I am using could be high density. I will try low density and see if that makes a diference when some is available. I will also try pc66 type memory, as I am using pc100 currently. however I do not see how bus speed would affect the amount of memory being accessed, typically incorrect bus speed would result in none of the memory being detected (at least none of the pc100 memory) or it would result in system instability (ie. windows would typically crash half way through booting because the clock rate of the ram would be unstable and would cause memory errors (often with memory intensive communications using DMA). however this is not my case, the machine runs stable, which leaves me to believe that the memory is clocking fine. Therefore I believe that problem could be with the bios. it maybe incorrectly interpretting how it can use the memory, and somewhere it is storing the usable amount of memory minus 64mb. I do notice that the usable amount of memory currently is reduced by 576kb which could be explained by some memory being allocated for some sort of cache or buffer. so it is possible that once the amound of memory passes a certain level, it misinterprets how much it can allocate for certain functions. I will try some other diagnostic tools to find a lowlevel reason for this.
If anybody is familiar with the rest of the address mappings for the bios, I would greatly appreciate you posting them here. Thanks.


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## StoneLion (Aug 30, 2006)

*Some additions to what I just said...*

I have some extra stuff here, but The system won't let me edit what I just typed in the previous message so I will repeat what I have just edited. 
First, in order to make editing the bios to disable the memory easier for people who may not have a computer science background I have changed what I said: 
I found some info on the internet and combined with what I already knew, here is what I have: I discovered how You can in fact disable the onboard memory.within the bios, go to the config menu. press ctrl-d. this will bring up a hex editor for the bios. within the base 128 bios go to hex address 2b (this would be row 20 column B in the grid), that byte must be edited such that the first bit is enabled. it appears that 80 is the common setting for this byte (which controls all the memory banks on the laptop. by setting this byte to 81 you can disable the bank that holds the onboard 32mb. (Be careful how you modify this area, if you screw things up, you won't be happy.) A quick computer science lesson for those who don't understand this system: the hex number 0x80 represents the equivalent binary number 10000000, changing the first bit (the least significant bit) will give you 10000001 which is 0x81 (if you do not know how to convert binary and hex in your head you can use the windows calcuator in scientific mode to convert bin and hex numbers). When the byte is edited, press F2 to save to the cmos, then exit the editor and shutdown the machine. (without exiting the bios setup). I believe you need to do it this was because if you exit the bios, it will save its settings overtop of the one you just changed, possibly undoing your work. When the machine started up again, I did see that the 32mb onboard was disabled, however, the memory in the second bank was still cut in half (my original problem involved the typical setup of 2 128 mb chips with the 32mb onboard showing up as 224mb). After disabling the 32mb onboard, the 2 128mb chips I have installed were used as 192mb total (the scond chip is still only used half way, so I ended up reenabling the onboard memory by resetting the 0x2B byte back to 0x80). Within the advanced diagnostic section of the bios (Go to the test menu and press ctrl-a), i did notice that the bios does infact notice that chip as a 128mb module. this would be because it simply reads the eeprom on the module and knows the correct size of the chip. So the machine recognizes Installed RAM of 294912kb (288mb) but Usable RAM of 228800kb (slightly less than 224mb).
Second:
So here is where I start to conjecture the many POSSIBLE reasons for the reduction in usable memory, so bare with me as I spit abunch of my thoughts out to the screen. I believe that it could be that the laptop is unable to address all 128mb of that bank (meaning the chip requires a dual bank socket) (Even software tells me that slot 2 only has 64mb ram in it even though the bios tells me it is 128mb) (I am using System Info by Gabriel Topala on the Bart PE Bootable CD to see this info). I believe that the memory I am using could be high density. I will try low density and see if that makes a diference when some is available. I will also try pc66 type memory, as I am using pc100 currently. however I do not see how bus speed would affect the amount of memory being accessed, typically incorrect bus speed would result in none of the memory being detected (at least none of the pc100 memory) or it would result in system instability (ie. windows would typically crash half way through booting because the clock rate of the ram would be unstable and would cause memory errors (often with memory intensive communications using DMA). however this is not my case, the machine runs stable, which leaves me to believe that the memory is clocking fine. Therefore I believe that problem could be with the bios. it maybe incorrectly interpretting how it can use the memory, and somewhere it is storing the usable amount of memory minus 64mb. I do notice that the usable amount of memory currently is reduced by 576kb (Installed RAM: 294912kb, Usable RAM = 228800kb, Difference = 64mb + 576kb) which could be explained by some memory being allocated for some sort of cache, buffer, or something else for controlling resources perhaps. so it is possible that once the amount of memory passes a certain level, it misinterprets how much it can allocate for certain functions. I will try some other diagnostic tools to find a lowlevel reason for this. The problem with this theory is that it does not explain why some people have been able to get the full 288mb (I have even read rumors of people getting more on this machine with larger chips, and I was able to use software (using System Info by Gabriel Topala) to determine that the maximum sized module for this machine is 256mb which would mean a theoretical maximum of 544mb ram). I must try low density pc66 memory before trying to hack the bios (which could be time consuming trying to figure out).
If anybody is familiar with the rest of the address mappings for the bios, I would greatly appreciate you posting them here. Thanks.


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## laboye (Apr 11, 2006)

If disabling the on-board RAM just decreases the overall RAM, I don't think it is worth it. While you present considerable information, it is not worthwhile. I do agree with the bank explanation and with high density memory, but I still don't see how your explanation would solve anything. Also, that's gotta be toned down for other users here... The 600 series has 2 banks per SODIMM slot, so it should be able to address the dual 128s even if they were high density. I highly recommend sticking with 228.


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## StoneLion (Aug 30, 2006)

From what I have been able to determine, only the first slot has 2 banks. the 3rd and 4th banks are the 2nd slot and the 32mb onboard. However I am still looking into this so you maybe correct. I am simply presenting it as a possibiliy. Afterall, if we don't present all possible info, we may never solve this problem. (I have come accros many people on other forums with this issue).
It is true that disabling the onboard ram just decreases overall ram. I was simply disabling it to prove the point that it will not allow the system to detect the 128mb module properly (as has been conjectured on many websites). My reason for suggesting lowdensity ram is that it was the original part listing for this model.
I will continue to post any information I discover in the hope that it will help others.


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## laboye (Apr 11, 2006)

Could this be a chipset issue? Perhaps the chipset is unable to address it.


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## sef-75 (Oct 18, 2006)

*IBM Thinkpad 600x Memory disable*

Hello all,

Just joined today after reading posts by StoneLion and wondering if anyone out there can help me out?

My Thinkpad 600x seems to report a base memory fault in socket 1 when running the IBM PC doctor and does not now load the OS!

It is the same when the extra installed memory is removed so I think could be a fault in the sys board included 64Mb.

Is there a way to disable this in a TP600x as say seems to be possible on a TP600 advised by StoneLion and just use the extra DIMM slot memory? Otherwise looks like I may have to consider a sys board replacement (sigh! ).

Thanks for reading!

sef-75


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## joesquire (Oct 17, 2006)

Hey
The most likely thing is that the missing RAM is for graphics, because the laptop i'm using now i wanted 512MB but it only has 448MB and i know that the missing 64MB is for the graphics because i set it to 64MB
So the missing RAM in your comp is 32MB for graphics i expect.
Because on my laptop i can choose, what i want from
64MB
32MB
16MB
and what ever i choose will be used for my graphics.
i'm 99.9% sure that im right with what i said

as you said your kaptop has 32MB ram intergrated. 
It could be using that 32MB integrated RAM and then taking 32MB ram from the actual RAM you put it and making the 64MB for graphics like my laptop has.


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## Supreme (Dec 12, 2007)

hey guys I have the same problem, I have a Thinkpad 600, 300 mhz running with Win Xp sp2, and the bios is updated. Memory: 32 mB integrated, and (2) 64 mB memory modules installed in each socket. But the computer is only reading 128 mB, when it is supposed to read 160-162 MB. Now this is weird because my computer use to read all the memory just weeks ago before this bios update (that I needed to run Winxp smooth) Also, i guess I switched the memory modules, putting them in different sockets that it was before. Now I check my memory using the last version of CPU-Z and it show me that my three memory sockets (1,2,3) are working (One 64 MB ram working just half) so that means that my in board memory is working and it is not disable... Anyways it is interesting to see that the processor is a Intel Pentium II Xeon. Because it is a Xeon, that probably means that use specific memory module, not any kind... ,more questions to this beautiful - hell computer... (My system once in a while freezes... now runs smoothly. don't know for how long. OS tweaked a lot!!! and clean win xp install, new bios; most probably memory defections or bios configurations ---- or maybe USB mouse/flash related???) bye and good luck


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## Ballistics2 (Jan 22, 2008)

I'm new at this, but it's just a thought. Someone said in an earlier answer that they had installed Crucial chips, and didn't have the problem everyone else seems to be experiencing with short memory. The only difference I can find in the Crucials and 99% of other memory on the market is Crucial for the 600 is a CL2, and everything else I find is a CL3. I don't know that in the over-all scheme of things if this is not a deciding factor with the IBM 600 series machines.


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## Supreme (Dec 12, 2007)

Hey guys I have found the answer. FOr thinkpad 600, and 600E, the FSB is 66mhz, so the memory has to be PC 66 compatible, now if u want to use the PC 100 you most probably will have to disable the in board 32 MB, ('cause is a PC 66) in the Bios. Search at google and you will find the way to edit it. 
I bought two 128 MB PC 66 at this link http://www.edgetechcorp.com/memory/upgrade.asp?cid=20192

They are 100% compatible and my Thinkpad 600 is running @ 288 MB with windows XP super ultra tweaked!!!! I use it to surf the internet and some open office documents. Sometimes for DVD playing my TK 600 runs @ 300MHZ only (expected to upgrade @ 400 MHZ MMC-1 pentium II in a future) DVD plays good with a DVD decoder PCMCIA card bus card, which helped to play DVDs on my laptop @ full resolutions.
For those with TK pads 600E upgrade the BIOS, abd I guess they can get full suport until 588 MB, and also they can get a special mod in the mobo for cool Pentium III upgrades. That is fun laptopto play with.


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## scunner3 (Apr 11, 2008)

I have same set-up as Joesquire but couldn't work out how on earth it came up with 448 MB - at least now I know. But excuse me if I'm going back over old ground but do you think I can recover 32MB of that? Or would a new (old) graphics card help?


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## TriggerFinger (Jan 30, 2008)

scunner3 said:


> I have same set-up as Joesquire but couldn't work out how on earth it came up with 448 MB - at least now I know. But excuse me if I'm going back over old ground but do you think I can recover 32MB of that? Or would a new (old) graphics card help?


hi, i think you can change that value in the BIOS settings under Advanced (not so sure which tab). if you need help on how to do this, just post back.


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## scunner3 (Apr 11, 2008)

Thanks I'll try it myself and when I've mucked it up I'll ask for more help.


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