Run curl loop in bash faster

Question

I've made a simple for loop to make POST requests using curl and save the output to a .txt file.

for ((i=200000; i<=300000; i++)); do
    curl -s -X POST -d "do=something&page=$i" "https://example.com/ajax" -o "$i.txt" > /dev/null
done

Currently, the script creates a new output in like every 260 ms. Is it possible to make this process even faster?