Thinkpad R40 memory problem

Hello, I´m new here and need some help.


I thought of upgrading the RAM in my Thinkpad R40. There´s allready one 512MB PC2700 module, and I bought a takeMS 512MB DDR400 module, as the older (PC2100 & 2700) modules are hard to find.
But after I installed it, the system is beeping 1,3,3,1 short beeps to indicate DIMM problem (as stated at Lenovo site).


Processor Mobile Intel Pentium 4M, 2000 MHz (5 x 400)
MB IBM 2681HTG
Chipset Intel Brookdale i845MP
System memory 512 MB (DDR SDRAM)
BIOS Phoenix (06/29/06)

The memory voltage cannot be set from the BIOS as there´s no option to control it.

Here´s the info on the existing module:

Module name Hyundai HYMD564M646A6-J
Serial no. 1C1F811Fh
Module capacity 512 MB (2 rows, 4 banks)
Mem. module type Unbuffered
Mem. type DDR SDRAM
PC2700 (166 MHz)
Širina modula (bit) 64 bit
Memory voltage SSTL 2.5
ECC Nema
Brzina osvježavanja Skraæeno (7.8 us), Self-Refresh
Max CAS latency 2.5 (6.0 ns @ 166 MHz)
2. Max CAS latency 2.0 (7.5 ns @ 133 MHz)

Any help appreciated.