How can ı use fully memory

Hi @Sorunlu3131!

A few more details would really help in diagnosing this issue, in the meantime here are some things you might wish to try:

Details that would help:

CPU Model / BIOS Version / Windows Version / DDR4 Model# And Settings Used (EXPO/XMP/Auto)


Some Advice (Please read carefully and understand the risks* when changing BIOS settings!)

First thing to check is whether you have a limit set in Windows itself, you can do that by doing the following:

1. Press the Windows key on your keyboard or click the Start/Windows button on the taskbar, type MSCONFIG, when the application "System Configuration" appears open it, it may take a moment to open/appear once clicked. Under the BOOT Tab, click the button in the middle of the window labeled "Advanced Options", and ensure that the "Maximum Memory" box on the right side of the window is NOT CHECKED! If it is checked and has a value, be sure to UNCHECK this box, click OK, then click Apply, then hit OK to close MSCONFIG, if APPLY is grayed out then simply click OK to close the applet. Restart the PC and check to see if the issue is remedied.

2. Does your CPU have Integrated Graphics? If so, your BIOS may be set to allocate 8GB to the iGPU for use as video memory.   This is more than likely the most probable cause of your issue if not the MAX Memory setting in Windows. References indicate that the buffer settings (UMA FRAME BUFFER SIZE) may be incorrectly set or have a corrupted value in BIOS. There are a couple ways to fix this, the easiest option is to enter your BIOS and set Optimized Default Values, this can typically be accomplished within your BIOS by pressing 'F9' to load the values and then when completed you simply exit the BIOS, selecting to save changes during exit and allow the system to reboot.

If you wish to modify ONLY the UMA Buffer Size setting, it can typically be found in the BIOS in Advanced Mode, under the Advanced Tab, then AMD CBS, Then NBIO Common Options,here UMA Mode should be set to UMA_AUTO and for UMA FRAME BUFFER SIZE also set this to AUTO. If you DO NOT have any custom settings in BIOS then I recommend the first option, set defaults with 'F9' then exit saving changes.

If this does not remedy your issue, you may wish to update your BIOS to the latest revision, if it already is at the latest revision, use the 'F9' option in BIOS to set the optimal defaults. If this doesn't seem to help, you may need to re-flash your BIOS to the latest version (even if it is the same as your current) if an F9 was not successful in fixing the issue. After a successful update/flash, immediately return to the BIOS and choose the 'F9' option to set defaults, click OK/YES and then exit the BIOS, click yes to Save Changes. Check in Windows to see if the issue has been fixed.

As defaults for DDR4/DRAM will be applied after a Flash/F9, ensure your DDR4 speed and voltage is set accordingly for your DRAM modules, if you are unsure, you can leave the defaults, although this will probably be a little less performant and not ideal especially with Ryzen as memory speed affects the clock speed of other elements such as the Infinity Fabric for example.

Ideally, you should set the XMP/EXPO profile for the DDR4/DRAM modules, but note that while an XMP/EXPO setting to the highest Profile or Auto will generally work without issue, you may face instability in some cases (depending on DDR4 module, speed, and die-type) that may require an increase to DDR4 module voltage to reach stable operation of the XMP/EXPO profile set in the SPD.

* PLEASE NOTE! Performing an Optimized Default Value load will reset any prior modified BIOS settings to their default/optimized state, so if you have any changes in BIOS that you have made, you will need to note them so you can change these settings back to your custom values after loading the Default Optimized Values with 'F9'. You will especially wish to take care to ensure your DDR4/DRAM settings are correctly reflected (Speed/Voltage/Timings) if you had custom settings set prior to the BIOS Flash or F9 usage.


I hope this helps, please report back whether this was successful or if you are still experiencing issues. Thanks, and good luck!

-Spikeypup