I'd recommend Prime95 as it will not only stress the CPU but test ram and other things in the process and let you know if your returning errors with your overclock, also logs information along the way. Just let it rip and call it good. I personally don't like to let anything of mine get past the 60-65 barrier at full load. If your hitting 70 at 4.4 vs 59 at 4.3, then I'd sacrifice the 100mhz in order to lower your temps by 11*C, that or get an aftermarket cooler if you feel the need to push it a little further. What PSU/Motherboard are you running with that?
If your going to get into the aftermarket cooler I was told the coolermaster 212+ is good. http://www.newegg.com/Product/Product.a ... 6835103065
If you do that your also going to want to use something like Arctic Silver 5 (an old standard) or some of the new overpriced stuff with crushed diamonds in it. I've been a big fan of AS5 since back in the early 2000's with my AMD Athlon system, worked wonder even with the stock CPU. But for the most part your going to see little results when it comes to using an aftermarket thermal paste with a stock aluminum cooler.
If you want to buy some other hardcore cooling products you can look here too. FrozenCPU.com. I haven't purchased much from there in a long time, but what I always loved on that site was their ability to carry coolers than no one else had. They also carry a high number of pure/solid copper heat sinks. If you have the choice of copper vs aluminum (assuming all other things like design are equal) ALSO go with the copper as it will move so much more heat.