The original European HTC HD2 came with a tremendous 448MB of RAM, enough memory to allow the device to be a true multi-tasking machine. Then came the Nexus One, which had a full 512MB of RAM. Now, according to HTC, the HD2 on T-Mobile will have a record-breaking 576MB of RAM, the most amount found on any smartphone that you can buy today. Additionally, the HD2 on T-Mobile will have 1GB of storage ROM instead of 512MB as found on the original.
Further, the fact that the device has 1GB of ROM means that it meets the Chassis 1 requirements for Windows Mobile 7 (which may not mean anything at this point), making the T-Mobile version of the HD2 the only device that will get an official WM7 upgrade.