Memory chips

I want to upgrade my RAM from 32 MB to 128MB or 256 MB. My PC is a clone with a  
mother board of
unknown origin which will take four 72 pin SIMMS and two 168 pin DIMMS. The CPU is a 
Cyryx M11  187
MHz. The present memory is SDRAM.


I am confused by the range of types of chips available and should be very obliged  for 
details or
the address of a site on the web where I can get them.
Many thanks
With kind regards,

Basil Grose