It is very unlikely that this is a problem in either libpng or zlib. If there were such a serious problem with either then I would expect that very many more users would be reporting it. In the case of zlib there is no CPU or motherboard specific code in there - exactly the same code runs on all systems of a given architecture and it is all pure memory operations.
If, as you believe, the problem is motherboard or hardware specific then it is much more likely that any software problem is in the kernel.
It is very unlikely that this is a problem in either libpng or zlib. If there were such a serious problem with either then I would expect that very many more users would be reporting it. In the case of zlib there is no CPU or motherboard specific code in there - exactly the same code runs on all systems of a given architecture and it is all pure memory operations.
If, as you believe, the problem is motherboard or hardware specific then it is much more likely that any software problem is in the kernel.