TestComplete Desktop v12.10 is very verys low to record and playback.
I am learning to record macros using the Orders application (C# version). Even the most basic operations, such as going to the file menu to open a file through the Orders application, is taking 30 s...
OK, on playback (and possibly recording), again it has to do with object recognition. In your NameMapping file, are you utilizing the "Extended Find" option on some of your objects? If so, one thing that is happening is that, when TestComplete goes to identify your object that you want to interact with, it needs to "find" it and the Extended Find does a breadth-first search of the component tree to find your object. The best way to get around this is to map additional "parent" objects in your tree to reduce the amount of searching needed.
Secondly, you say that the majority of the problem happens on opening a new form. TestComplete needs to recognize that the form exists and child objects on the form exist before it can proceed. So, if you click on a button and it opens a new form and you want to do something with that new form, TestComplete needs to first find that form before it can interact with it. There is, in Tools | Current Project Properties | Playback an option called Auto-Wait Timeout. Most of the time, this defaults to 10 seconds. If TC needs to recognize your components before interacting, this wait may come into play. If it's something other than 10 seconds, that's probably where your long delay is.
Finally, under tools | Options | Engines | NameMapping there is an option for "search for visible objects first". Turn that off and see if that increases your performance.
Beyond that... since there are not too many other people reporting the same performance problem, this could be something localized to your environment. Try temporarily disabling virus scanners and such in your test environment, double check your memory and processor levels, etc.
Also, it might help us if you can post pictures of code segments of where the problem is occurring and, perhaps, screenshots of the full Advanced properties listing of the objects in question in your TestComplete object browser.