Please try the enclosed.
This is not yet stress test, but I used subroutines from Freescale stress test sources.
Below are instructions how to use :
1. Connect UART and COM ports of host PC and your i.MX35 board.
2. Run script "mx35_com_load.bat" from the package in order to load and run
the codes to internal RAM of the i.MX35.
3. Check if codes are loaded correctly, using log file "a.a".
4. Run TerraTerm (or Hyper Terminal) in 115200, 8,1, n mode on host PC.
5. Check is there are no error messages on the terminal during relatively long
time (~several hours).
Sources are enclosed too, therefore (if needed) some adaptation for
specific DRAMs may be implemented by customers.