Help needed to make amd r9 m375 gpu workable in Lenovo z51-70

This a well known problem with Laptops which use AMD and INTEL Graphics. Apple uses a feature called AMD Switchable Graphics in this particular case which means that the intel HD Graphics will be your primary output to save Battery Life as long as there is no high demand on the graphics subsystem and automatically switches over to the AMD Graphics if demands rises. Unfortunately this won't work on Hackbook's since they are designed to work with Windows in the first place and use a slightly different technique to make things work. The only way to make your AMD Graphics work is to use it as the only present Graphics which means you'll have to deactivate the IntelHD Graphics on Bios Level or find a way to do manipulate your DSDT in such way that it hides the iGPU so that OS-X won't see it and therefor also won't initialise it.

@OliverZ maybe you could give us a hint how you did it on your Setup?

Hello @ypdeveloper,
hello @griven,

I set up my hackbook with the Lenovo Z51-70 one year ago. At that time I used a BIOS which allows direct access to the advanced bios ettings. In the meantime I did two upgrades of BIOS which locks the advance bios settings for the user. The DSDT.aml which is used by ypdeveloper has no conflicts with the installed hardware components of his model (80K60002IN). I am using the model (80K6003VGE) with the same graphics card.

The only chance to make the AMD R9 M375 running is to make changes in the DVMT-table and some inputs in the DSDT.AML together. Otherwise it will not work. I found some hacks that ensures that the advanced bios settings will be unlocked for the user. There is no quarantee that this will work with the Lenovo Z51-70. The only way is to try it out.

I will make a test installation with my configuration on a separate harddisk to check if I find a solution.

The problem is that Lenovo made a restriction in the bios which ensures that the user has no direct access
to the advanced bios settings. I must be a version before the 2.xx number mayme 1.9 or something like that.

If it is possible to install an older version there exist a hidden key combination with the "fn" key together with another
key to get access to the advanced bios settings. I forgot that key-combination. But we can find it out, if we are able
to install an older version.

Within the DSDT.AML you must inject the AMD R9 M375 with the device-id, the ram-size and the framebuffen. Then it will work. The Intel HD5500 will be defined as the second graphics card.