I have an Aspire5733-6650 that came stock with one 2 GB stick of DDR3-10666. I replaced it with one 4GB stick of PNY DDR3-10666 from Best Buy. I dont know what the timings are as laptop BIOSes almost never give the user the ability to change or view that info.
Anyway, when I turn the computer on with the 4GB stick it just randomly tuns off, usually within 45 seconds. I was able to boot into Windows once and Windows did regonize that 4GB was in the computer, so it sees all the RAM. I tried both DIMM slots, and I exchanged the RAM for a new stick. The 2 GB OEM stick works fine, the 4GB one wont. Google says the computer supports up to 8GB sticks.