First of all, you don't need to isolate non-Filipinos for your posts. The tech world is very large and full of enthusiasts who will gladly advise you on different aspects of your device, or any device-related topics.
I am from the Philippines too, kababayan, and I had the Lumia 625 before. Black loading screens are normal, but stutters are not. The older GPU's probably the culprit. Lumia 625 sports an Adreno 305 while the Lumia 720 has only Adreno 225, if my memory serves me right.
Next advise is it would be better if you buy from online sellers than from these Nokia outlets around the country since the tax imposed is huge. I bought my Lumia 625 for only P8680. The downside is that there's no warranty for the device (which is like a tool only for giving you peace of mind) and that you should be wary of what version of the device are you buying, since the network bands for your device may not be compatible for the network bands in our country.
Congratulations for being another 'Lumian' and mabuhay!
Sent from my Nokia Lumia 1520 (RM-937 Malaysia) using Tapatalk