I am getting horrible memory leaks. the client starts at about 1200 MB of RAM usage, and gradually climbs to about 1600 where it becomes very slow
it takes about a match to a match and a half to result in this
Me too !
You can easily see in Task Manager that memory allocation is increasing continuously.
After 2...4 games the client crashes reproducibly
I can 100% confirm this behaviour.
After 2...4 games, the client crashes with ~2GB memory allocated.
It sounds like you may need some more troubleshooting advice, please submit at: https://mtgo-support.wizards.com/hc/en-us/requests/new and select 'Technical Troubleshooting'.