Steam frame and expedition 33

Is the steam frame expected to be able to run vr games or is the stand alone frame strong enough?

I'm also interested in expedition 33 on my 4k tv. But I don't think the steam machine is near strong enough to run 4k right? Is there a big difference between 1440 vs 4k? I guess there's also low medium high settings that's just as important.

Just on the fence whether I should get a machine.