U have told/asked as poor network... network is related to signals from tower as i know...speed test is related to Data..it differs according to signals recieved in mobile..low signal will give less speed and good signal will give good speed generally...loading/opening sites mostly depends on compatibility of DNS ...maybe few other technical things too effect..
So if ur question is on network signals then we can do very less to improve...in low signal areas very few handsets/brands recieve sufficiant signals for our data usage but on same location few brand handsets may not recieve good signals...