I recently bought new memory for my Imac from 2008. When I inserted the memory I decided to first check it with Memtest OSX. I did let it run for 3 cycles without any fail. After I did run Memtest86 and it did produce a few errors during the first 2 runs. During the 3rd run it produced an enourmous amount of error pointing to a heat issue. An internet search on the reliability of memtest86 on Imac's did not produce much results. Which tool should I actually believe?