Memtest OSX pass but Memtest86 fail

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?

 

I did get the impression memtest OSX was performing similar tasks as memtest86 with the only difference that it would miss a very small amount of memory.

I used memtest86. i'll try memtest86+ this weekend. I'll keep you posted on the results. Have more people observed issues with Memtest86?

 

Last night I did try memtest86+ and this one actually passes (4 passes)

So the results are now:
- Memtest86: fail
- Memtest86+: pass
- Memtest OSX: pass

Can I assume my memory is actually OK based on these results or do I have to do some more testing?

 

My machine is running fine but currently I'm not using it very frequent.

I don't agree with your feedback. You can also run a diagnostic test to evaluate new HW. Right now it's easy to return the memory in case of failure. If I find out after half a year or worse after one year it will be more difficult (despite the waranty).