It does have 320Mb ram
Thats total! The actual amount you see free is whats left after the baseband, camera/media/fb/gpu0/gpu1, kernel, touchwiz and running programs use.
For example the galaxy with 192mb ram shows about 40mb free - and thats with no fancy touchwiz etc. The Hero, with 288mb, shows 65mb free because it runs rosie UI etc.
On another note, here's a copy of a post i made on xda-developers:
So the phone has the same 7200 processor as the Galaxy (528Mhz), and 320Mb RAM.
Its security locked, and has no fastboot. There seem to be bootloader protected partitions inside some security container. On reboot, if a modified system or boot partition is detected it will restore the running partitions. Thats why a modified su doesnt stick.
We tried flashing a modified samsung recovery to the behold using the Odin samsung recovery tool, and it was accepted. But on reboot it was restored again to stock
That means without a bootloader hack its not going to be possible to run custom roms on this phone.
One workaround is to use a loader or rebooter, which will boot a modified boot partition that you store in an unprotected area. Its not very elegant tho