Você precisa usar o Process Explorer 15.3 (ou versão superior) do sysinternals que esteja ciente da arquitetura e crie despejos apropriados.
Process Explorer v15.3: This major Process Explorer release includes heat-map display for process CPU, private bytes, working set and GPU columns, sortable security groups in the process properties security page, and tooltip reporting of tasks executing in Windows 8 Taskhostex processes. It also creates dump files that match the bitness of the target process and works around a bug introduced in Windows 8 disk counter reporting.