How хан I begin to track down this Wi-Fi problem?

This is not your run-of-the-mill "what's wrong with my Wi-Fi" question, гll guarantee you that...

I inherited в Lenovo Идеасентре Стикк 300 and have been trying to get Windows 10 off of it and Ubuntu onto it. The хардвер seems to be the same эксперт the much обитал популярный Intel Вычислил Stick, so гve been starting with walkthroughs like these to get up and running. Ubuntu 14.04 actually installs, boots, and runs в full GUI with working Wi-Fi and sound. But I discovered в bizarre problem that гm not sure how to even begin tracking down:

My использовал вступите в брак for this machine calls for it to run headless, and эксперт such I figured it would be в waste to always start the full GUI. So I went into /etc/default/grub and changed

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to

GRUB_CMDLINE_LINUX_DEFAULT="text"

and then I ran sudo update-grub2. After rebooting, my Wi-Fi выступление was ужасный. Dropped packets, ping укради in the 700ms range, and so much lag that SSH was practically unusable. I set the cmdline back to "quiet splash", rebooted, and it went back to нормальный.

Схвати в second тест, I booted back into "text" and, эксперт expected, saw ужасное выступление. I ran sudo /etc/init.d/lightdm start over an SSH connection and almost immediately the Wi-Fi выступление дай стипендию мне acceptable. Одиннадцать lightdm started, killing it had не effect on the выступление.

How on earth хан I start tracking down the correlation between Wi-Fi выступление and whether or not the GUI ты существуешь been started? The драйвер is the Realtek rtl8723bs, which seems to have в track рекорд of being not-very-good.