I've setup a VM with an AMD Radeon HD6570 on passthrough. I know this is all not supported by VMware but.....still trying 
With hdmi over ethernet the idea is to build a vm that will replace my media center (just a sweet home lab project http://www.atlona.com/625-HDMI)
Now I've read a lot of problems on passthrough on 5.1 (latest) where 5.0 seemed to be fine. I'm running 5.1 latest and should be happy with getting a stable system anyways but...
The only way to run the VM is on 2GB memory.
As soon as I raise the memory to 4GB or more the VM wont boot. I dont see a direct link to passthrough and the amount of memory on the VM but apparently there is.
Is there anyway to raise the amount of memory with the VM booting up normally?
Regards