if i remember correctly there is a fix to enable more ram for fallout 3. ya gotta fiddle around in the .ini files.
ah jeah, totally forgot that there is now a SE version of skyrim. some mods still aren't ported to the newer version unfortunately x.x.
your method of making sure it works is no doubt an effective way of preventing crashes, but damn does it waste time. ya gotta sit for a whole day just to setup skyrim >.>. well, at least mod organizer 2 is much better than the shit you have at hands for fallout 3.
You can also get more memory by using ENB but you're still capped at about 4GB for Fallout 3 and Skyrim LE since they're 32 bit. Not an issue for Skyrim SE or Fallout 4.
As far as porting oldrim mods, you can easily port almost anything that doesn't require a DLL yourself. With a few minor exceptions all you need to do is just unpack any BSAs and run the meshes through NIF Optimizer and you're done. I've run into a very small number of cases where NIF Optimizer is unable to convert a mesh and when that happens you'll get an immediate crash when you enter the area where whatever that mesh goes to is visible.
Sometimes you can use the oldrim mesh instead but sometimes it just won't work unless someone manually fixes it. As an alternative I've found that Ousnious is actually really good about updating NIF Optimizer if you send him an example of a mesh that it doesn't work on. Presumably that would also expand it's capabilities to work on other meshes that have that same issue. Out of the thousands of meshes I've converted I've found a grand total of 1 that NIF Optimizer didn't work on.
The main exception is face/head parts but I've found that you can just use the oldrim version for that and it works fine. NIF optimizer gives you black faces if you try to convert that stuff so you would have to regenerate your own head parts with the CK to truely convert that stuff.
Most people recommend resaving the ESP in the CK but that's not really needed. About half of the mods I use in Skyrim SE are oldrim mods I converted myself and they work fine. This includes oldrim sexlab mods like SLEN that work fine in SE (although I think there's an unofficial port of that one now anyway).
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