Does anyone know if .psd files created in Photoshop on a Mac are compatible with Photoshop being used on a regular PC machine?

Im getting a funky 'not enough RAM to open' error every time i try opening a .psd file and i know it was orginally created on a Mac but, i also have another .psd file that was also created on a Mac that opens fine.

Does anyone know of any compatibility issues with different OS versions of Photoshop and Macs/Pcs?

Regards,

Lee