All other things being equal, how much is the difference between 2 channels for memory and 4?

[MattyS22]

So let's pretend everything is equal on 2 machines I'm building. One version of the processor has 4 memory channels, the other has 2. In each machine I use 4 sticks of RAM. How much better is the performance on the machine with the processor that has 4 memory channels, all other things being equal? Said better, what are the advantages of the machine with 4 memory channels?

 

[dasa]

Systems with 4 channels are often at a disadvantage in a lot of software as the extra bandwidth comes with a hefty latency hit.
If you are using software that thrives on high memory bandwidth then the quad channel system will get a nice boost to CPU performance.

 

[GotNoRice]

I recently made the upgrade from an Intel 5820K with quad-channel DDR4 to an AMD Ryzen 3900X with only dual-channel DDR4. For the first week or so, I even had to re-use my older DDR4 modules from the 5820K setup in my 3900X. It really did not seem to limit or hurt anything. Even when using several VMs or more at the same time, where you might think memory bandwidth would come into play.

 

[Archaea]

Is sissoft sandra still the way to benchmark memory scores?

 

[dasa]

AIDA64 is probably more popular these days.