I want to upgrade the RAM in my Acer Aspire 5736z-4826.

Hello and yes in some cases it says that it can take 8 gig max and most places it says it takes 4 gig max in 2 slots of DDR2 2gig. Also you could get a 1 gig stick and have 3 gig is able to run as well... 

2GB Module - DDR2 800MHz

Part Number: KAC-MEMG/2G  

Specs: DDR2, 800MHz, Non-ECC, CL6, X8, 1.8V, Unbuffered, SODIMM, 200-pin

you can get that from Kingston,

http://www.kingston.com/us/memory/search/Default.aspx?DeviceType=3&Mfr=ACE&Line=Aspire&Model=67583&Description=Kingston_System_Specific_Memory_for_Acer_Aspire_5736Z_Series_(DDR2)

Or you could if you wanted to use the scanner from Crucial. or you could get the ram from them here... 

http://www.crucial.com/usa/en/compatible-upgrade-for/Acer/aspire-5736z-4801

Both memory sights say 4 gig max... However Crucial doing the search says it is DDR3 12800 1.35V However you did say that didn't work well. So I would assume that it is the DDR2. I have a Laptop that I have ddr3 in but it only supports ddr2 and just was able to work with the ram just not as fast if it was in the machine it was ment for...

James