Hmm... I'm not so sure it will run on such a low end machine. As for installing the game, I recently installed RA3: Uprising via Origin. It was not an especially pleasant experience, installing the game, but it worked without fiddling. Just constantly restarting Origin and doggedly restarting RA3:U until it was able to connect to the DRM-validating server.
So far, without any tweaking, RA3:U is running somewhat poorly with my i7-4930k and EVGA 950. I don't really have time tonight to work on it, but tomorrow I'll look into it. Apparently there is a DX9 thing GSLS, or something like that.
Not very helpful, I know, but it's something.
edit: I installed RA3 the same way as Uprising, which went well enough. No difficulties, just annoyances. However, getting the game to run properly is going to be a completely different story I fear. I'm not having any trouble with the 3D graphics, but the 2D videos slow the game down tremendously.
edit2: Hmm. I've tried a few things, but the audio still is coming out choppy and whenever a video is playing the frame rate tanks.
edit3: Okay, I've sort of fixed it. I just need to narrow down WHAT fixes it. Pretty much I removed all dll over rides, and now the game runs perfectly. The trick will be to find WHICH over ride, and then set a program specific registry key.
edit4: turns out the culprit is dsound. changing that from "native" to "builtin" fixes all of my issues at least.