Unofficial maximum memory specs

Some ThinkPads are known to support more memory than their specs say. This page gathers information about those models, how much memory they can take and what special requirements that memory must fulfill.

Have a look at the Memory page for the official memory configs and partnumbers

Working memory configurations

The following table gives an overview of tested memory configurations that exceed the specified limits for that ThinkPad type.

ThinkPad	max. Specs	BIOS	Embedded Controller	Memory configuration successfully tested
ThinkPad A31p 2653-R	1 GB	1.09	1.05	2 x Kingston 1GB 200-Pin DDR Model # KTM - TP9828/1G
ThinkPad T30 2366-92U	1 GB	2.08	1.06	2 x Kingmax 1GB 200-Pin DDR SO-DIMM DDR333 (PC2700) Model # MSAD42D-KI but see problem with T30 not booting with 1 GiB memory module. 2 x Generic Brand 1GB 200-pin DDR SO-DIMM PC2700 (p/n 89898E): BIOS recognizes 2048MB, but Gentoo sees only 1024MB
ThinkPad T43p 2668-WTB	2 GB	1.29	1.06	2 x 1 GB (Kingston KTM TP3840/1G DDR2 533MHz)
ThinkPad X31 2672-C2G	1 GB	3.02	1.08	2 x 1 GB (Kingston KVR400X64SC3A/1G DDR400MHz) Boots with 1 bar. Newer documentation also states 2 GB, although original one did not.
ThinkPad X31 2673-C2G	1 GB	3.02	1.08	2 x 1 GB (Team Group INC. TSDR1024M400 DDR400MHz) Boots with 1 x TSDR1024M400
ThinkPad X41 2528-5FU	1.5 GB	2.09	1.02	1 x 2 GB (Transcend TS2GIB3847 DDR2 667 MHz) 1 x 2 GB (FRU 73P3846 DDR2 PC2-4200) BIOS claims 2.5 GB. Diagnostic POST tests only 2 GB. Linux and XP recognize 2 GB.
X41 Tablet 1866-6HU	1.5 GB	2.03	1.02	1 x 2 GB (Transcend JM667QSU-2G DDR2 667 MHz) BIOS claims 2.5 GB. Diagnostic POST tests only 2 GB. Linux and XP recognize 2 GB.
ThinkPad 240 2609-40U	320MByte	IRETWWW76	n/a	Any PC100/256MByte memory in 16 Chip Configuration will do
ThinkPad 240X	256MByte	unknown	n/a	Some PC100/256MByte memory in 16 Chip Configuration may work. Chipset cannot handle more than 256MB
ThinkPad 570 2644-3AU	320MB	1.16 IMET65WW 11/11/99	n/a	Kingston KTM-TP390X/256 256MB MODULE FRU 16P6327 - 16 Chips 8 each side
ThinkPad 600  ?	288MB	?	?	416MB = 256MB low density PC-100 SODIMM + 128MB PC-66 SODIMM + 32MB PC-66 onboard (Note: it matters which SODIMM you put in which slot. This was first reported working on the Thinkpad Mailing List, and it worked error-free for me when I tested it.
ThinkPad 770x 9549	448MB	1.11 IIET42WW 09/10/99	n/a	448MB = 256MB PC-100 + 128MB PC-66 + internal 64MB using IBM 256MB MODULE FRU 33L3070 PC 100 CL2 - 16 Chips 8 each side. 512MB = 2 x 256MB PC-100 + 64MB internal booted up as well. 512MB is due to 440LX-Chipset limitations, 64MB are overlapping or unused.

Non-working memory configurations

ThinkPad	max. Specs	BIOS	Embedded Controller	Memory configuration unsuccessfully tested
ThinkPad A21m	512MB	?	?	2 x Microx 144-pin 512MB PC-133 SDRAM SODIMM 32x16 8C 1 x Microx 144-pin 512MB PC-133 SDRAM SODIMM 32x16 8C 1 x Microx 144-pin 512MB PC-133 SDRAM SODIMM 32x16 8C + 1 x 144-pin 256MB PC-133 SDRAM SODIMM

External Sources

• IBM's official Memory compatibility page