System Specs

[Vern1701]

I suspect that some of the errors that have been reported are NOT THUD-related, but rather users' systems not being current enough to run the 64-bit version. Memory leaks do not inherently involve the THUD process, and might be a combo of the D3 and THUD processes with D3 eating up at least 60% of the RAM and CPU. Sure, there are other issues with the 64-bit client, but in order to cut out the memory leak issue:

Make sure your GRAPHICS drivers are up to date. This might be what is causing the leaks and NOT the RAM,
Terminate all other programs running except D3 and THUD and essential BACKGROUND processes. Some programs eat more memory than others and might be causing THUD to leak the excess memory.
Before downloading the next version, read the version notes posted and don't assume anything. Check your system specs to ensure that THUD will run properly.
Finally, the 64-bit D3 client does have some issues itself that are completely unrelated to THUD. Check out the main forums and/or do a search for common 64-bit client issues.

It is NOT recommended to use an older system (> 5 years old), unless it has been upgraded to support D3/THUD. Even an OEM OS (Win 7 w/ SP1 and latest NET) will NOT run the current recommended specs for D3. They are:

Blizzard Support for PC (use recommended specs only, even these are a bit low and need to be updated)

You will notice that Win 10 is recommended for D3 gameplay. Win 7 is a minimum requirement and may NOT be able to run D3, depending on the system.

[NMP]

Windows 7 64bit and my system IS older than 5 years. (xeon 1231v3..) I run 4x D3 multiboxing without any problems...

[Vern1701]

Notice I say recommended and not minimum. If you DO have minimum, keep your specs current in all phases. This includes Win 7/8. Also, notice that the specs come directly from the game site.