Recently Amibroker released their - and according to Amibroker the world's - first 64-bit native "technical analysis platform for individual traders." The 64-bit version seem to support all current x64 processors from AMD and Intel. The software is able to leverage the underlying 64-bit hardware to it's fullest extent: up to 1 TB of physical memory and up to 16 TB of virtual memory. According to Amibroker the software performs 25% faster on 64-bit.
According to other sources, Amibroker is the world's second. MultiCharts has been the first 64-bit software in this area. Don't know who's right. Can't even find confirmation that Multicharts has a 64-bit version.
Be it as it may, there's 64-bit TA software out there using the "64-bitness" to offer better performance and added value to customers. Great!