VB6 program hangs (slows) Windows 7 64-bits but not in 32-bits. Any solution?

We have a program coded in VB6 running well on Windows7 32-bit with a Dual core, at any time. Now we are trying on Windows7 64-bit (dual core), and our surprise is that it's not working so fine: In long process, long loops, the system becomes saturated (hangs with 50% processor use) and it's impossible to change to another program (for example: ALT+TAB doesn't work or works very slowly), like 5-10 years ago, when our computers had only one processor or core. Any idea? Any limitation? Any bottleneck with 64-bit SO and VB6 runtime?

Old-fashion and not elegant solution at this time: I can fix this with Doevents (We've tried it, and it works) disabling and enabling all the controls, but it's full of enabled/disabled controls and it's hard to manage this and return the correct state

Thanks in advance.

Update Info: If we are running 2 applications based on 32 bits mode (it notes in taskmanager like *32), when one of them hangs the Windows7, the ALT+TAB works fine between 32 bits appli开发者_如何学运维cations and GUI works fine. But if we change to an application using 64 bits, the GUI doesn't reponse.

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OK, thank you for your comments. At the end, after 3 days, we found the problem!

After a lot of buildings with differents paths in the code, we found a method that enables the tooltips on a Farpoint Spread v7 with the methods (textTip/textTipDelay):

fpspreadControl.TextTip = TextTipFloating 
fpspreadControl.TextTipDelay = 250

This control is contained on a Form that never unload, only we hide it. If we unload the form or we comment these two lines of code, the problem disappears. Maybe Matt had the right path to the solution, some Timer in the control that launch the tooltip event hangs or hooks something in the system.

Thx again.