ThinkPad 770X/Z The Maximum Memory Saga Continues

[DK6400Brian]

It's really strange.

The ThinkPad 770X/Z has 3 memoryslots. DIMM-0, 1 and 2
One of them holds the 64 MB PC66 SD-RAM Basememory in DIMM-0.
This slot can't be reached, other than if you disassemble the machine almost completely.

If you max the machine out with 2x256 MB in the other two slots, the basememory is ignored.
That's funny.
That doesn't happen with 1x128 MB + 1x256 MB nor 2x128 MB

I previously assumed, that the basememory in DIMM-0 shared a bank with one of the other slots and that the machine had given the banks in the user-upgradable memoryslot higher priority.

But hey...nada baby !

I just went through SiSoft Sandra that could report the following back to me:
---------------------------------
System Memory Controller
Location : Mainboard
Error Correction Capability : None
Number of Memory Slots : 3
Maximum Installable Memory : 512MB
Bank 0/3 - DIMM 0 : Empty
Bank 1/4 - DIMM 1 : DIMM Synchronous 256MB/64
Bank 2/5 - DIMM 2 : DIMM Synchronous 256MB/64
---------------------------------
and...
---------------------------------
Logical/Chipset 1 Memory Banks
Bank 1 : 128MB SDRAM 2-2-2-0
Bank 2 : 128MB SDRAM 2-2-2-0
Bank 4 : 128MB SDRAM 2-2-2-0
Bank 5 : 128MB SDRAM 2-2-2-0
Speed : 1x 66MHz (66MHz data rate)
Multiplier : 1/1x
Width : 64-bit
Refresh Rate : 15.60µs
---------------------------------

I'm getting very curious here.
The 64 MB basememory is still in the machine, but completely ignored.
Still SiSoft Sandra tells me, that bank 0/3 in DIMM-0 is free

I've just spend the last two nights, reading Sharedoc's very comprehensive efforts to tweak his Thinkpad 600E to the limit.
I thank you, Sharedoc and I appreciate it very much
They (The L2BIOS-disable, FSB108-mod and SS-mod) will be used later on my P-III 850 MHz MMC-2 module/ThinkPad 770Z.

Now.....Something tells me, that something is tasting one or two of the banks in one of the user-upgradable memoryslots and if it's used (by a 256 MB 2-bank module), then the 2 banks (bank0/3) in the basememory is ignored.

That's why no one can ever put 768 MB RAM in a ThinkPad 770X/Z.
The chipset is 440BX, but it supports 4 slots, 8 banks with up to 1024 MB in total.

Has anyone got any idea about what's going on ?
Is there a bit or byte than can be changed/altered in order to liberate the DIMM-0 slot from the chains of ignorance ?

The BIOS is: IOET23WW available from here:
http://www-307.ibm.com/pc/support/site. ... IGR-47F3VA

Kindest regards and I thank you in advance.

Brian

[Sharedoc]

Interesting. This doesn't happen in 600E, where 544M is the max (it has 32M soldered in the mainboard).

Anyway, the benefit of the last 64M on top of 512M is marginal.

[Sharedoc]

Where did you get the 850MHz-PIII?

[DK6400Brian]

It was on sale on Ebay.

It very rarely happens, that the MMC-2 850 MHz is for sale.
If it turns out right, I will be having at least 15 [MMC-2 P-III 850 MHz CPU-cards] within a couple of weeks.

When it happens, they'll be set for sale here at Wim's BIOS and the ThinkPad-forum [at forum.thinkpads.com] for $90.00 each + shipping.
The rest will go on Ebay.com for $140.00/£75.00/€110.00 + shipping, fixed price !
Anyway. Wait for the news to break. I'm not taking reservations or orders before then. Things can still go pretty wrong.

Sharedoc
I've asked IBM if they're having the CMOS-maps for the BIOS'es in the obsolete 600 and 770 series public available.
I haven't heard anything yet.

I am very grateful to you and your terrific work.
Clearing up the CMOS maps in manual, is hard work.
Learning by error, sort of speak.

Do you have any hunch of it could be a bit in a byte, in the CMOS, that determine that the machine ignores the base-memory DIMM, when instering a 256 MB stick in one of the user upgradable DIMMs ?
And perhaps which bit in what byte, that could be interesting ?

I think I got it right, that a bit in a byte can set the machine to ignore the base-memory.
I think that was one of you're first steps here, with your 600E.
Making the machine ignore the 66 MHz stick, soldered to the mainboard, in order to use 100 MHz RAM, without running into trouble.

If it can be done with the 770X/Z, then it would be possible to have 768 MB installed.

The 850 MHz CPU-card was installed yesterday, and it works just fine.
The 127-error is fixed, thanks to you.
Now the SpeedStep-mod and FSB108-mod is in sight.
In theory, this will give 918 MHz on an old ThinkPad.

The thoughts of exchanging the CPU itself should also be possible.
Although it seems hard, difficult and...yeah impossible

Kindest regards
Brian.

[DK6400Brian]

And by the way.

The 64 MB modul in DIMM-0 can be taken out and replaced, when you dissamble the machine.

I don't know which of DIMM-1 or DIMM-2, that swaps DIMM-0 out, when inserting a 256 MB stick, so don't hang me.
Let's assume it's DIMM-1, then the following is the case.

DIMM-0,DIMM-1,DIMM-2

64 MB, 64 MB, 64 MB : OK
64 MB, 128 MB, 128 MB: OK
64 MB, 128 MB, 256 MB: OK
64 MB, 256 MB, 256 MB: Not OK. DIMM-0 ignored.
128 MB, 128 MB, 256 MB OK
128 MB, 256 MB, 128 MB: Not OK. DIMM-0 ignored.
128 MB, 256 MB, 256 MB: Not OK. DIMM-0 ignored.
256 MB, 256 MB, 256 MB: Not OK. DIMM-0 ignored.

The machine has 6 banks capable of recognizing 128 MB each.
A 256 MB 16-chip RAM-stick, has 2 banks of 128 MB each.

Perhaps the machine tastes, that it's okay using one bank in DIMM-0.
Using two, swaps the DIMM-0 out.

The DIMM-0 can't take a 256 MB either, if I remember correctly.
......now I'm getting doubtful here !!!
I need to ask James at ThinkPads. He's the one.

Perhaps it's a matter of logic.

Bank 0/3 - DIMM 0
Bank 1/4 - DIMM 1
Bank 2/5 - DIMM 2

Using a 128 MB stick in DIMM-0, takes use of either bank 0 or 3.
Using a 256 MB stick uses both.

Same goes for DIMM-1

I wonder if the machines is tasting for memory in bank 0 and 1.
If bank 1 is used, it swaps out both bank 0 and 3 in DIMM-0

............Sharedoc...let me get back to you.
I need some more information regarding using a 256 MB in DIMM-0.

Later...

[Sharedoc]

in 600E byte 2B of CMOS controls the SDRAM banks. Bit b0 disables internal 32M memory. By changing the content from 80 -> 81 the 32M is disabled.

Bits b1 ... b7 control other memory banks.

Here is my trial log (I don't remember how much memory I had installed, propably 32 + 128 + 128)

Initial value 80
81 (disables internal 32M)
82 and 83 ?130M
84 228!
88
90 294
A0 228M!
C0
7F no post

[DK6400Brian]

Sharedoc

If Byte 2B equals Byte 43 in the CMOS Base 128 matrix, I can go looking.
Can you verify this ?

Brian

[DK6400Brian]

I got it.

Went straight into the CMOS.
Byte 2B has a value of 80 here too.

Took pictures of all 17 different screens inside the CMOS of ThinkPad 770Z with my cell-phone.

Gotta think, gotta see, gotta research, gotta.......

Brian

[Sharedoc]

Propably 6 of the bits disable a memory bank. Each memory module has 2 banks. The order I dont know, but you can find it out by occupying different memory position with different size modules 32, 64, 128. Then turn on bits one at a time in 2B and observe post how much memory it finds.

Another option is to seat memory module in different positions and then try fifferent bit positions to turn it off.

[DK6400Brian]

Okay.
Here's the result.

ThinkPad 770, P-233MMX, TX-chipset.
Onboard-DIMM-0: 32 MB, Bank-0
DIMM-1: 128 MB, Bank 1-3
DIMM-2: 128 MB, Bank 0-2

Installed RAM: 294.912 KB
Maximum usable RAM: 228.800 KB

The 64 MB in DIMM-2/Bank-0 were ignored.
Bank-0 in DIMM-0 had highest priority.

Bit b0=1 disables Bank-0, but don't liberate Bank-0 in DIMM-2.
Result: 196.032 KB

Bit b1, b2, b3 =1 disables something on Bank 1,2,3 and leads to error.
Result: 163.264 KB

Bit b0+b1 or b2 or b3 disables 2 Banks in a row.
Result: app. 130.000 KB

Bit b4+b5+b6+b7 = 0 or 1 have no effect.

Byte 2B, initial value: 80, RAM 228.800 KB

81: 196.032 KB. Onboard RAM ignored.

82: 163.264 KB, Sandra couldn't launch. Error.

83: 130.000 KB.

84: 163.264 KB, Sandra couldn't launch. Error.

85: 130.000 KB.

88: 163.264 KB, Sandra couldn't launch. Error.

89: 130.000 KB.

90: 228.800 KB.

A0: 228.800 KB.

C0: 228.800 KB.

Odd combinations:

91: 196.032 KB. Onboard RAM ignored.

A1: 196.032 KB. Onboard RAM ignored.

C1: 196.032 KB. Onboard RAM ignored.

F1: 196.032 KB. Onboard RAM ignored.

F0: 228.800 KB

8F: ERROR. No boot.
I guess all banks are ignored, and not even BIOS can copy itself in order to boot.

8E: Didn't try, but I guess it'll show about 32.000 KB, since only Bank-0 is open.

Hmm...too bad. No luck in Byte 2B

I did try with my daugthers ThinkPad 600 with P-II 300 MHz, 440BX-chipset.
Same thing goes. No luck.
Same results.

Now......I'm dead tired and I'm off for tonight

Tomorrow is another day

[Crossposted in forum.ThinkPads.com]

Kindest regards
Brian

[cmarti]

Brian/Sharedoc,

Did you ever find th eway to get the thre slots to work withn 256mb rams?

I know it is an old thread but good.

[Sharedoc]

Does 770Z have built in 32M RAM on the motherboard? Maybe it can cut away and additional SODIMM slot wired instead? It may require a lot of work though...

[cmarti]

Does 770Z have built in 32M RAM on the motherboard? Maybe it can cut away and additional SODIMM slot wired instead? It may require a lot of work though...

No it has a removable 64mb ram and you can install three 256mb rams but only two are recognized.

Here is a picture where you can see the memory slots.



I hope that helps.

[Sharedoc]

I wonder if the 770 limitations are due to motherboard being designed for TX chipset rather than BX chipset in mind.

[edwin]

430TX can only support up to 256MB so that doesn't make sense either.

What happens if you remove the 64MB removeable and put in a 256?