As it turns out all HTC HD2 units actually have 576MB of RAM, but only 448MB of those are available to the users.
It’s a bit more understandable when they disable a GPS or an FM radio unit – you only need new software to utilize it, but we just can’t figure out why would HTC hide a big chunk of RAM on their flagship. And heck it wasn’t even the only feature disabled by default on the HD2 powerhouse. Remember the Wi-Fi 802.11n support that you have to enable on your own?
So, it’s not only the units headed for T-Mobile USA which pack more RAM, but all HTC HD2 smartphones out there actually have 576MB aboard. You only have to unlock the hidden amount of memory using some custom ROMs.
It can be done by going to the xda-developers forum and read this thread. Then get the needed ROM up and running on your HD2 and enjoy the extra amount of RAM memory. Just be careful, because it will most probably void your warranty.