Don't ask how to hack password. (BIOS Passwords)
#31443 by DK6400Brian
Thu Apr 28, 2005 2:19 am
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 8) 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 ? :idea:
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