Thinkpad W541 With EC2, NGFF/M.2, Thunderbolt 2 - so many options!
I've been looking at the excellent https://egpu.io/external-gpu-buyers-guide-2018
I'm trying to figure out which way to go to plug a GeForce GTX 770 into a Thinkpad W541 and I'm hoping I can lay out what I've learned about my options and you can correct any misapprehensions I have.
According to this link the W541 has a crippled TB2 port that runs no faster than TB1 (8 or 10 Gbps)
Since bandwidth sucks and TB2 enclosures are also expensive and hard to find these days this seems like a non-starter.
The W541 has two NGFF M.2 slots for WiFi and WWAN. The WWAN one is unpopulated in mine which would be convenient if I could use it.
Here is a picture of the slots:
The WiFi socket is A-Key and has an A/E Wifi card in it.
The WWAN socket is B-Key which according to https://en.wikipedia.org/wiki/M.2 supports PCIe ×2 just like A-Key.
Unfortunately, there doesn't seem to be a version of the EXP GDC that supports B-Key.
I've been hunting around for a A-Key to B-Key adapter but it doesn't seem to exist.
Even if I did plug the GDC into the A-Key slot and get a usb WiFi adapter (or a B-Key WiFi adapter if such a thing even exists), according to https://egpu.io/external-gpu-buyers-guide-2018/#m2-interface I would only get 1X PCI 2.0 bandwidth of 4Gbps with my 4th gen i7, so no better than EC2 anyway.
If the bandwidth is going to be the same between EC2 and M.2 then I think I'd rather just use EC2 since it's so much simpler.
Thus the decision is EXP GDC for ExpressCard.
Does that all make sense?
Just wanted to thank you for the summary. I have a different laptop Zbook 15 G2 and everything you mentioned confirms with what I've read so far on other topics. With the only difference, the TB2 port on the Zbook is not crippled, but the EC2 port is very much useless. So I think the only possible options for my scenario are:
1) TB3 enclosure with TB3>TB2 adapter
2) ADT-Link R43SG-TB3 dock. Unfortunately I read the TB3>TB2 adapter is a no-go for this dock as it requires 2W to power on something on the board. So this might be a problem unless ADT revise the board and get that power from the PSU or a new TB3>TB2 adapter which carries power is released on market, which considering TB2 is totally obsolete, is HIGHLY unlikely.
So yeah, i think I am pretty much stuck with option 1.