How to identify low density ram?

[idea]

I have a BX133 chipset mobo, only accepting low density sticks. Someone has a 256mb PC133 "double sided" for sale. How can I be sure this is low density and will be compatible? What should I ask?

 

[Peter]

BX133? Intel 440BX chipset? Then you need "16x8" geometry SDRAM.
Double-sided 256-MByte sticks usually have 16x8 type chips on, but on the cheap stuff sometimes there is 32x4 stuff that BX can't use.
Your best bet is to look at the markings of the SDRAM, visit its manufacturer's web page to identify what it is. If the manufacturer is unidentifiable or nowhere to be found on the WWW, you better avoid that DIMM anyway.