Write Speed far less than "advertised"

[RonRN18]

I have a Memorex 12x BD-R Writer and have some BD-R media listed for 1x-4x. ImgBurn reports the device of my Memorex burner to be "Memorex BDBurner 800L v1" and that it has a maximum write speed of 2x. I was expecting quite a bit faster write speeds than 2x, where it takes about 45 minutes to burn each disc. I know with the media being 1-4x, I should theoretically be limited to 4x, but ImgBurn will only do 2x. I realize that my Memorex burner was probably not the wisest choice for a burner, but was wanting something fairly cheap and it was under $100. I just don't know if the limiting of speed to only 2x when the drive is advertised at being 12x is related to the drive itself or a limitation within ImgBurn, which is why I'm posing my question here.

[LIGHTNING UK!]

It's a drive/firmware/media combo thing and nothing to do with ImgBurn.