Supporting this investigation is Team Group with their T-Force Vulcan Z DDR4-3000 memory.
But what all this means is, yes it’s possible for four modules to improve performance over two modules in a dual-channel system.ĭemonstrating that we’ll look at a series of benchmarks conducted using a Core i9-9900K and Ryzen 9 3900X processor. How much of an impact this has on performance depends on the application and the memory controller's ability to take advantage of open pages. Although the ranks can’t be accessed simultaneously, they can be accessed independently and this means the controller can send write data to one rank, while it waits for read data previously selected from another rank. This can give the four DIMM module configuration an advantage as it allows several open DRAM pages in each rank. However, when using four single rank modules for dual-channel operation, the memory is now configured as a dual-rank. So when using two single ranked modules for dual-channel operation, the memory is configured as a single rank. This is important to note because in the tests we’ve seen all memory used has been single-ranked modules. In fact, there is very little difference between one dual-ranked module and two single-rank modules when connected to the same memory controller, even though the memory chips reside on different PCBs. A system populated with more than two single-ranked modules will actually act as if dual-ranked modules are installed. Things get even messier when you introduce more memory sticks or modules. A module with chips on both sides of the PCB is just dual-sided, and can still be a single-ranked module, so it’s a bit confusing. Typically, single rank modules feature all memory chips on one side of the PCB, while dual rank memory places chips on both sides of the PCB.
Identifying if your memory is dual or single rank can be difficult as software doesn’t always read modules correctly and not all memory manufacturers note the rank in the modules' ID. Most consumer grade memory features a single rank, though higher capacity modules are usually dual rank, while server grade memory is often quad-rank. For those of you unaware, the term ‘rank’ means the number of 64-bit memory banks on a module. We believe this due to how the memory is configured or more precisely, the memory ‘rank’. However, we've seen tests around showing an increase in performance by adding two extra modules, allegedly without increasing memory frequency, or improving timings.
In this scenario all modules are operating at the same frequency, use the same timings, and provide the same total memory capacity.ĭual-channel platforms such as AMD’s AM4 or Intel’s LGA1151 require two matched memory modules for dual-channel operation, adding a second pair will only expand memory capacity and won’t upgrade you to quad-channel memory, for that you’d need a Threadripper or Cascade Lake-X processor. It's not unusual to have this kind of question debated in tech forums, so today we're having a look at the performance impact of having four DDR4 memory modules in a dual-channel system, opposed to just two modules.