First, lets get it clear... there is a difference between kb/s and kB/s
b = bits
B = bytes = b x 8
Tixati's BW limits are set in BYTES, kB/s
so an incoming limit of 1500 kB/s is 12000 kbits/s
What level of BW does your ISP supply you with? Have you done an online speedtest to see if you are getting what you are paying for?
I am confused by this:
I set my incoming bits to 1500 or 2500...so as not to limit my incoming bits
Setting a limit does just that..."limits your incoming bits" (as bytes)
use some internet search engine with this:
site:tixati.com limit bandwidth
read the first 10 or 20 results and you'll learn from numerous posts on this forum in the past.
and of course:
http://www.tixati.com/optimize
finally, outgoing limit has a crucial impact on download speeds. We'll get into that later if need be.