It takes about 10 seconds total for the game to load on my system (about one second for the loading screen to pop up, three seconds for the game to start, and five~six seconds to get past the second loading screen).
My processor is dual-core; since GM doesn't support multithreading it runs on just the one core, which would be approximately 3 GHz.
I have 2 GB of RAM, but am currently using the Windows pagefile (which I have set to 8 GB) since I've been doing some extremely high-memory stuff recently.
My video card is the not-all-that-great NVIDIA GeForce 6600 LE, made even worse by its inclination to overheat, but since GM supports only minimal hardware acceleration, this doesn't mean much - and it certainly wouldn't affect the loading screen.
Finally, my disk transfer rate is rather slow, which is probably limiting the speed. Unfortunatlely I don't know what it is exactly.