Note: This file discusses x64 capabilities. If you want to read about 64-bit double precision audio processing (which is available in both x86 and x64 versions), take a look at 64-bit processing.
Note: The following information is only useful if you have a x64 CPU and you run an 64-bit OS. If you have an x64 CPU but your OS is 32-bit, or if you do not have a 64-bit CPU, then this information is only useful for educational purposes.
Turbo Play is also available in 64-bit version. The 64-bit version is capable of the following things that they are impossible in the 32-bit version:
When running the 32-bit version of TP, you have access to 4GB of ram at most. Because the upper 2GB is reserved by Windows for the system, you actually have only 2GB at most. You probably know that there is a trick that would tell Windows to give you 3GB of ram, but your VSTs are usually not compiled to support this feature, and, even if TP x86 is able to handle up to 4GB, your VSTS probably aren't, so using the 32-bit TP restricts you to 2GB of ram.
When running the 64-bit TP, you can access your entire memory. However, 32-bit DLLs (like 99,9% of VSTS) cannot be loaded under an x64 host. For this reason, TP x64 implements a "ghost loader", with 2 additional files found in your TP directory, VSTWOW64.DLL and VST32.EXE. VSTWOW64.DLL is an 64-bit dll which is actually loaded to TP when you load a VST, and VST32.EXE is a 32-bit program that loads your VST, gives it the entire 4GB of RAM, and sends/receives the midi/audio data through VSTWOW64.DLL , which then passes it to TP. This process is transparent to you and you will configure your VST in the very same way you would configure it when running under TP x86. In other words, when using TP x64, not only you can use your 32-bit DLLs, but you will give them all of the RAM they might need.
At the time I write this information, I realize that only a few VSTs by now are that memory-hungry? Think again! Load 1 full orchestra and one full piano, and you will need some 3-4 GB of ram! Using a 32-bit sequencer can never get you more than 2GB of ram for your VSTs!
In addition, TP x64 can only load an 64-bit ASIO driver. However, the same trick appears in file ASH32.EXE which loads the 32-bit asio driver, then passes the information to TP x64 so you can load a 32-bit asio driver under TP x64 as well.
If you run the 32-bit version of TP but you still have an 64-bit OS, the 32-bit TP can still load an 64-bit ASIO driver (via ASH64.EXE) and an 64-bit VST (via VSTWOW32.DLL and VST64.EXE). So if you insist running the 32-bit version of TP for compatibility reasons (for example if a compression codec is only available as a 32-bit dll), you can still access 64-bit devices.