Yes and no. You could run the 650ti for your display and the 610 for physics, but can't run them in SLI. For SLI they have to be matching models (i.e. 650ti and 650ti) The memory does not have to match as it will only use the lower amount (i.e. 650ti w/2gb + 650ti w/1gb, would run as 2x 650ti w/1gb)