How many memory testers do we need?
UBCD is full of tools that are "almost" the same. How many boot managers do we need? How many partitioners do we need?...
As oppose to other tools, RAM diagnostics depends on several aspects; one of them being hardware support (each tool may have different requirements / compatibility issues), and the algorithm being used.
For example, memory diagnostics running under Windows, in general won't be so exhaustive, since part of the RAM is being exclusively
used by the OS.
OTOH, DOS memory diagnostic tools should be more reliable, but they still depend on an algorithm to alternatively "free" the RAM so it can be tested (an to use alternative patterns to test it). That's why some tools won't find problems in some cases, but other memory diagnostic tools are successful. In other cases, the first tool will success, and the second would fail.