Why is my iPhone 4 Internet so slow even on Wi-Fi

I made sure I deleted all my app history and nothing so I then turned my phone off for about 20 minuets and still nothing. I've had my phone for about 5 months and it just started happening. Should I take it in to the apple store or just rest to factory settings?

Sometimes if the wi-fi connection is slow by itself, it can slow down browsing from the iphone. I found, in my house, when my signal is weak towards the back of the house, I have to turn off wireless to browse the web. Even though, signal shows 2 bars, it doesn't seem to be enough, at LTE data at those spots are 10 times faster.

If, your experiencing the problem everywhere, I would suggest, backing up your iphone, and then resetting it to default factory settings, and try restoring from backup. If it is still slow, I would try to reset back in to factory settings, and see how it runs without restoring the backup. (this is to eliminate previous settings that may be impact to it). If the iphone is fine, then I'll suggest there's something corrupted in the file from your previous backup/config. If it still acting slow, then at this point, I would suggest its a hardware issue, and should check with Apple about replacement.