Advanced EE Help Needed

[dedakia]

Hi all,

 

I'm trying to create my own eGPU (with a twist) and would really appreciate some help!

I want a device that I can use for 2 different purposes:

1) As a eGPU to let me game using my Macbook Pro (via Thunderbolt)

2) An independent desktop computer capable of gaming (has its own CPU, RAM, HD)

 

The problem I'm having is figuring out a good way to interface the GPU with 2 different sources and switch between the two. The current solution I can think of is creating a custom PCB which takes splits the GPU PCIe bus into 2, one of which is active depending on the orientation of a physical switch. This would take a lot of effort, with the added difficulty of interfacing with Thunderbolt - which seems to be restrictive of the devices they allow.

 

Is there a simpler way to do this that won't require designing a PCB?

 

Or is there any company selling this type of chip?

 

Thanks in advance

[Another Tech Inferno Fan]

1. "Engineering" implies practicality. The simplest solution is often also the most practical. Physically move the card.

2. Please don't create duplicate threads.

3. Perhaps you could program an FPGA to connect 4 lanes (Thunderbolt only does 4 lanes of PCIe) from the card, and then connect that to either a thunderbolt line (in eGPU mode) or a desktop motherboard slot (in desktop mode). Should be as simple as just reading the binary value on one side and passing it through to the next. I don't know what kind of bandwidth requirements you may need.

4. I spent 5 minutes searching on Google and found this: http://www.nxp.com/products/interface-and-connectivity/interface-and-system-management/pci-express/pcie-channel-switches:MC_52251?cof=0&am=0&tab=Products
 

This device from TI shows an application diagram in section 10.2: http://www.ti.com/lit/ds/symlink/hd3ss3415.pdf

Edited June 15, 2016 by Arbystrider