What’s the difference between 64-bit and 32-bit dxdiag

32-vs-64-bitdirectx

I'm doing some logging and noticed that on 64-bit platforms I can use the /64bit switch to run 64-bit dxdiag. I assume there must be some reason for doing this, namely additional functionality in the 64-bit version (or incorrect/insufficient functionality when using the 32-bit version on x64). What exactly are the differences?

Best Answer

From personal experience, dxdiag can also be used to determine if there is a problem with the 32 or 64 bit portions of the drivers. For example, running dxdiag in 32 bit might show no acceleration for DirectDraw or D3D; yet running DXDiag64 might show everything as fine.

This is useful when trying to figure out video issues, particularly since most games execute in x86 (32 bit) mode only.