It's a bit off-topic here, but just too to clarify - I've been doing it on very slow connection (16 kb/s), and on very fast one (faster than N900's wifi chip can handle, so it was limited by hardware, not server bandwidth, or mine).

I *used* to have same problem as you describe, looong ago, before moved swap to microSD exclusively *and* I've applied swap-related settings like ones, that I recommended in ED thread (based on freemangordon's ones, just tweaked a little). Since that, no problems, no matter how big files I download, move, extract, or compress. I've compressed whole ED images to lzma (and de-compressed them) on device, being able to do other things on it without major slowdowns - from browsing, to talking via phone.

IIRC you have tried my settings without good results and it puzzles me. But, I'm absolutely sure that correct setting have potential to fix such instabilities, as those are clearly results of so-called "swap hell" - maybe some devices need other settings (could eMMC chips be different between production series?)? Or maybe fact that my swap on SD is 2GB in size have something to do with it, too?

/Estel