RAM,single/double sided how to tell?

I know that single sided RAM has modules on one side and double sided on both sides but how can you tell from the tech spec when trying to buy the stuff?

I bought Kingston ValueRAM 2GB (2x1GB) 533MHz DDR2 Non-ECC CL4 DIMM from
http://www.kikatek.com/product_info....oducts_id=1116 for the ECS mobo I have but only half the amount of RAM is shown on POST, I've read about this before but never had this problem so after a quick look around the web it seems this is caused by using single sided RAM when double sided is needed, I contacted ECS about this before going any further and they confirmed that double sided RAM is needed, SO WHY DON'T THEY SAY SO IN THE BLOODY MANUAL!!!
Sorry rant over, it just infuriates me when something so simple as this is not mentioned in any of the mobo specs.

The RAM is for the DOSBox mod I'm building and is not a high spec PC, it uses a ECS P4M800PRO-M2 Micro ATX mobo and the manual states,
Supports DDR2 533/400 DDR SDRAM DIMMs
• Accommodates two unbuffered DIMMs
• Up to 1 GB per DIMM with maximum memory size up to 2 GB

To me nothing in that spec identifies that double sided RAM is needed and having had a look at the RAM for sale at online shops single/double sided isn't mentioned and most of the pictures of the RAM are just generic pictures of RAM so how are you supposed to know?
Obviously I'm no RAM expert but have I got it all wrong and missed something, just how do you know which is single/double when buying RAM?

My Beta-brain is confused again :neutral: