A clue to problems of that type is a deterioration of signal quality in bad weather. So, before going any further, test your modem on a different phone line. I have two lines here, and while they both sound good for audio quality, one of them will allow much faster connections. If that does not work for you, your game program has modified registers. Note that I am talking about registers, not the Registry.
Modems have some built-in nonvolatile memory.
All of them are based on a common standard developed originally by Hayes. You will need to study your modem technical manual to see which registers affect speed. Most of them can be changed. This is a complex subject beyond the scope of this column. However, let me say that there is a way to restore the factory defaults.