Can you provide dmesg from failed suspend on 64-bit kernel? I bet it will fail differently than 32-bit kernel.
2 256MB cards + 32-bit kernel without CONFIG_HIGHMEM4G (only 876 MB of RAM directly accessible) = fail. Maybe it's fixable, but I wouldn't count on it.
Can you provide dmesg from failed suspend on 64-bit kernel? I bet it will fail differently than 32-bit kernel.
2 256MB cards + 32-bit kernel without CONFIG_HIGHMEM4G (only 876 MB of RAM directly accessible) = fail. Maybe it's fixable, but I wouldn't count on it.