Just about any inexpensive aftermarket cooler will be just as good if not better than the stock cooler. Something like a cooler master hyper t4, raijintek themis, raijintek aidos, bequiet pure rock are all good options. Just be sure the cpu cooler height fits in your case and you should be good to go. The 212 evo and cryorig h7 are also good options though a bit overkill maybe for a locked cpu like the 6500 and run just a little more expensive than those others. The ones I suggested would be at least a good budget starting point.