recommended memory stress test for TX1

Can someone recommend a memory stress test that works on the TX1?
Preferably freeware

If you go to this URL, click on “hardware”, and then “testing” check box, you should find the memory characterization tool. This is likely what you want.
https://developer.nvidia.com/embedded/downloads

As you know, Jetson TX1 is module + carrier board, the memory is in module and is verified to pass stress test before ship out. So no need to do additional memory stress test.