提高插入符号模型训练速度（R）

I have a dataset consisting of 20 features and roughly 300,000 observations. I'm using caret to train model with doParallel and four cores. Even training on 10% of my data takes well over eight hours for the methods I've tried (rf, nnet, adabag, svmPoly). I'm resampling with with bootstrapping 3 times and my tuneLength is 5. Is there anything I can do to speed up this agonizingly slow process? Someone suggested using the underlying library can speed up my the process as much as 10x, but before I go down that route I'd like to make sure there is no other alternative.I have a dataset consisting of 20 features and