Why Is My Memory Slower than Expected?

Due to anomalies in reporting software as well as system and configuration limitations, new memory may not function at full speeds or may report what appears to be lower performance than expected. There are several reasons for these issues, some of which are simply misunderstandings in how DRAM operates and others which can be overcome or offset by changes to your configuration.

Modern DRAM modules support double data rate (DDR) transfers, meaning that although they function at a given clock speed, they transfer data during both the rise and fall of a CPU clock cycle, allowing for double the data transfers their native speed, or frequency, would suggest. Some diagnostic or system information software does not express this clearly, only reflecting the modules' frequency in megahertz (MHz), making such feedback suggest that your parts are only running at half their possible speed. For example, DDR5-5600 supports 5600 megatransfers per second (MT/s) due to its nature as DDR memory, but runs at 2800 MHz. HWiNFO64® (shown below) is one such application reflecting speed in MHz, while the MT/s value is shown alongside it, though not all applications show both values.

Another factor in this reporting comes from your system's CPU and motherboard. One of these components (typically the CPU in mainstream hardware) will feature a memory controller which may only offer support for a particular maximum frequency of memory, and as a result can bottleneck your module performance. To verify what your other hardware will natively support in terms of DRAM speeds, refer to both your CPU and motherboard specifications.

This factor can be compounded by the MHz/MT reporting differences. A DDR5-5600 module in an environment capping its performance at DDR5-5200 speed may report 2600 MHz during diagnostics under these conditions.

Multi-channel support from your system's motherboard results in additional performance above the installed memory's individual part capabilities. A dual-channel configuration using two identical DDR5-5600 parts effectively doubles their bandwidth, resulting in performance approaching 11200 MT/s. At this level, however, practical gains are not always easy to notice, and in some cases, simply increasing your memory total (for example adding a single 8GB part alongside an already installed 2GB module) may be most of the benefit you will receive from a given upgrade. We offer our parts in guaranteed matching kits to assist in taking full advantage of this feature in systems which support it.