I have an old 2010 13" macbook pro thats about similar, it kind of chokes compared to a desktop.. but you definitely should be able to run 200 oscs~
its probably the FX - maybe there's a cheaper reverb out there (they use delay lines) or maybe use delay lines more sparingly
it might also be the UI if you have a PD screen full of number boxes, sliders, other things that are giving feedback all the time, reducing the amount of responsive UI can help
if you are using two monitors try just one, definitely close browsers and other apps, turn off the network
but yeah upping the delay msec setting is usually where you go to try and fix it, you're right around the threshold I run into when I jam in netpd with that laptop. theres a patch you can open with your patch running - its called test audio and midi and listen to the sine wave - if it crackles or sounds weird while your patch is on try setting the delay msec up until its good.
leave the block at 64 - a lot of stuff expects it to be 64, so that can only cause weirdness.
It isn't as much latency as you think it is because its 64+that setting, as little as 2. this is different than something like JUCE which just says its a power of two buffer. it would be 104 at 40. vs 128 is the lowest usually offered
side note: testing the round trip settings in the extras I was able to set it down to 3 on an intel mac. 2 with asio and a roland dac on a pc. quickly had to turn it up when I started working on complicated patches tho