New server kinda crashy

It's not more rough than if it was done manually, but the more often it happens... Lets just say, expect to be replacing components more frequently. Cheaper in the long run to upgrade the memory. I'm guessing you're using the standard atx/mid tower instead of an expensive server, so you should be able to take up to 32 GB. I'd go with the G-Skill memory. It's cheaper, but without sacrificing quality either. Also make sure your page file size is up to par with the physical memory. Probably at least half of whatever you have installed so 16 GB page file if you have the full 32 GB installed. If that is in fact the cause of the problem this will help at least.

It might be just that the Avatar mod isn't as light weight as we'd hoped. I have noticed one unforeseen consequence with the air bending. It allows you to airblast jump pretty far pretty fast, and if you are good enough you can chain multiple airblast jumps to gain some real distance. Doing this has caused me a fair bit of lag even on my big computer. This is not exactly caused by the airblast jump, but rather by the server trying to catch up with me and load chunks. Maybe it would be possible to have a cool down time for the airblast jump. A few seconds ought to prevent people from using it to travel in this way. I don't want to nerf air bending though. We really need that technique to be able to run from fire benders.