I want to be able to generate a random data file in Windows using either CMD or PowerShell, with the generated data being comprised of lines and lines of random text. I've managed to achieve this in PowerShell using the following command, however this took around 1 minute to generate 1MB of data, which is way too slow to be generating GBs:

`1..100000 | % { [System.Web.Security.Membership]::GeneratePassword(70, 3) >> C:/dummy.txt }`

File output should be the following:

```
YyS@ZRU98udC3q#R@5o7AR$*Bh44v22J!ekKSpIAgLQyp^pbBx
s8Wm589aYYH39@Arb2^ZRMPjx2UaEwHYkMmhgFaU$QyAU@@@WU
yB^!qo6e4x*eFvx%ZY7738&&FkhHXU24OCJCxfyQ7a%peo!$ap
...........
...........
$GVhMrkZfJbIkgAgri0w9lFVt6a^vXh6ev&jwPHGfoE!pVW85r

```

Does anyone have any suggestions? Preferably I can do this without the need for external tools, as the script to create this data will be run automatically during startup of the machine.