What OS is installed and what AMD driver is present?
How do you know one device is disabled? Do both appear in Device Manager?
I would recommend updating your system with the latest available drivers from the Lenovo website. Your system should have been configured correctly by Lenovo so that it was working out of the box, so to speak.
I know one is disabled because when I check AMD catalyst it shows the R9 and the R7 and lists one as enabled graphics and one as disabled graphics. I think they decided to run the A8 as a simple CPU and the R9 as dedicated graphics and skip the cross fire all together. I'm running windows 10, not sure which driver I have at the moment, they all installed on startup.