If when buying Memory sticks of the same value as but different Brands,.You find later that they have totally differing Latency numbers which are often omitted from the retailers description of the Specs!

So, if I brought a Latency value 9 stick with a value 13 installed previously, what if any Issues would happen? Would there be a lag ?
I do note that SIW reads the Values off well ,but does not give any Latency Numbers

For the record the values go from 5 to 15 (May be also a 3 but am unsure) the lower number is "faster"
Is there any RAM ID tester Program that declares Latency Numbers?