ASUS offers a new method of overclocking DDR5 RAM called DIMM Flex in its updated motherboards based on the Intel Z790 chipset. It is intended to not only improve memory performance, but also increase the stability of overclocked RAM modules.
There are two main methods for overclocking RAM. Increasing the operating frequency improves RAM read and write speeds. By adjusting the timings, the delay in operation is reduced. The problem with modern DDR5 kits is that they get very hot under load, which not only limits their overclocking potential but also reduces their intended performance. ASUS internal testing has shown that DDR5 RAM performance can drop by more than 22% when it heats up under load.
DIMM Flex is intended to solve the problem described above. To this end, ASUS has installed a temperature sensor next to the DIMM slots on certain models of its updated Z790 motherboards. The data from the sensor is processed by a special controller on the board and then sent to the CPU, giving it the command to change the RAM frequency. Formally, it is about the dynamic change of the working frequency of the RAM, taking into account load, temperature and some other parameters. In this case, temperature information from the internal PMIC controller on the memory modules themselves is apparently not taken into account.
The company explains that the Flex DIMM can significantly improve frame rates depending on the game, chosen screen resolution and game settings. For example, in the game Metro Exodus running at 1440p resolution, Extreme quality settings, and DIMM Flex enabled, the FPS increase was 17.59% compared to the default RAM settings. The new DIMM Flex feature provided a performance advantage even over the optimized XMP memory overclocking profile. The latter only increased performance by 1.35% in this game compared to the default memory settings. In Counter-Strike: Global Offensive, the XMP profile was able to increase FPS by 5.26% at 4K resolution, and the DIMM Flex increased FPS by 10.53%.
DIMM Flex is activated in the Ai Tweaker menu item in the motherboard BIOS. Once a DIMM Flex is enabled, the AI Overclock Tuner automatically switches the memory overclocking profile to XMP Tweaked, the most appropriate value for the DIMM Flex. When using memory modules without XMP support, you can select the AEMP II or DIMM Flex profile in the Ai Tweaker tab.
After that, you can keep all default settings or manually set restrictions on temperatures and times. DIMM Flex offers three levels of adjustment based on variable temperature setpoints, allowing extreme performance settings at low temperatures, less aggressive settings when RAM warms up a bit, and even lower performance settings when the memory temperature threshold is reached. Level 1 settings correspond to those specified in the root DRAM settings menu (Basic or XMP profile). For levels 2 and 3, you can select smaller timings to tailor RAM performance to your usage scenarios.
The company has published a list of motherboards as well as RAM modules that support DIMM Flex. With him you can Check out the manufacturer’s website. We are mainly talking about boards and RAM modules from the ROG series with support for frequencies from 6800 MHz. Unfortunately ASUS is in his Notice does not specify whether DIMM Flex technology only works with 14th generation (Raptor Lake Refresh) Core processors or whether it also works with 13th (Raptor Lake) and 12th (Alder Lake) generation Intel chips can be.