What's the difference between Kingston's KVR13N9S8 KVR1333D3N9?

[shabi_e]

Hi,
What's the practical difference between Kingston's KVR13N9S8 KVR1333D3N9?
I saw that the only difference in the specs is the Refresh to Active/Refresh Command Time (tRFCmin), which is 260ns for KVR13N9S8/4 and 160ns for the KVR1333D3N9/4G (both are 4GB DIMMs)? how does this effects the performance of the DIMM?
Can I mix both DIMMs on an H61 motherboard?

Thanks!

 

[Agera One]

Don't mix RAM sticks. There are no guarantee they'll work together.
tRFCmin belongs to latency and there are only few programs which affect from them. The MHz and CAS Latency are the most important for almost all applications out there.

 

[littleleo]

KVR13N9S8/4 are 8 chip the KVR1333D3N9 are 16 chip. back in the day when DDR3 1st came out older systems used to need the 16 chip but I think call the current motherboards run 8 chip just fine.