WiFi speed degraded upon clean installation of windows 10

Trust not Windows Update, for it knows not what it does to third party equipment. Anyone who had nVidia video cards shortly after Win10’s first slew of auto-updates knows this well.

It’s a safe presumption that Windows will do nothing but check dates on drivers it can reach, compare them to drivers you have, and if it just “thinks” that the new driver is the right one, it will overwrite them. What it will not do is check the manufacturer website; it gets its drivers from Microsoft’s database.

Download the driver specific to your machine here. Please note that Windows 8 is as high as is supported by Dell for that equipment, but the Win8 driver will (most likely) work.