BIOS only detect half of my RAM :(

[Ram 2 GB]

I have 16GB RAM (4x4Gb) Corsair Vengeance LPX 2666Mhz.
But Bios only detect half of my ram 8192MB, but CPUZ, and Windows detect 16GB. but in task manager Memory Perfomance only detect 8GB.
anyone can help? 

Ooh, and everytime i try to change my speed or voltage my PC is reseting something then back to American Standard screen. And i need to press F1

This happen after i change my GPU from Rx480(died) to GTX 1660.
My full spec :

R5 1600 
Asus B350F Strix
Msi GTX 1660 6Gb Ventus Sc
4x4 Corsair Vengance 2666Mhz
Be Quiest Sytem Power 8 500watt

[SupaKomputa]

Clean the ram first with an alcohol swab.

Plug the ram one at a time and run Memtest86.

[Turtle Rig]

5 minutes ago, SupaKomputa said:

Clean the ram first with an alcohol swab.

Plug the ram one at a time and run Memtest86.

Also he can try X.M.P for the heck of it.

 

Also this really has nothing to do with it but run DDU "Display Driver Uninstaller" in safe mode and do a clean and reboot then your back up in normal mode and now install the latest nVidia WHQL drivers and let us know after trying what was suggested up top.  What Im saying which is not really the reason for the hole your in but it is something good to do especially when you switch from AMD to nVidia or vice versa.

[clutchmaster]

ram detection issues well what i do is use rubbing alcohol to clean the ram and remount the cpu after splashing some alcohol on it drying after of course and trying each stick one at a time then both
if it shows up in bios then ur good if not in the OS if windows 7 ur gonna have to reinstall the os
if windows 10 u may have to run windows update then restart computer win10 sometime doesnt like to detect more ram if it has updates more comen with fresh installs of win10 even with 19** something

[Ram 2 GB]

4 hours ago, Turtle Rig said:

Also he can try X.M.P for the heck of it.

 

Also this really has nothing to do with it but run DDU "Display Driver Uninstaller" in safe mode and do a clean and reboot then your back up in normal mode and now install the latest nVidia WHQL drivers and let us know after trying what was suggested up top.  What Im saying which is not really the reason for the hole your in but it is something good to do especially when you switch from AMD to nVidia or vice versa.

I alread tried the XMP profile, but every time i pick one, my PC restart back to American Trend

 

3 hours ago, clutchmaster said:

ram detection issues well what i do is use rubbing alcohol to clean the ram and remount the cpu after splashing some alcohol on it drying after of course and trying each stick one at a time then both
if it shows up in bios then ur good if not in the OS if windows 7 ur gonna have to reinstall the os
if windows 10 u may have to run windows update then restart computer win10 sometime doesnt like to detect more ram if it has updates more comen with fresh installs of win10 even with 19** something

I see thanks, im gonna reseating the ram one by one

 

4 hours ago, SupaKomputa said:

Clean the ram first with an alcohol swab.

Plug the ram one at a time and run Memtest86.

Okay gonna try it

[Ram 2 GB]

I AM SO DUMB !! So one of my stick didnt click. After i pressed it gentle l heard click sound, and i am so surprised. 

Sorry i am so careless

i just sad my GPU died 2 days ago, and only last 2 years, and i'm scared when i press it too hard will damage my other component. Thats why my ram didnt seat properly.

 

Thanks for bothering u guys

[toysniper]

It happens, Sorry to hear your GPU died.  What were you using?    Pro tip if you buy from Microcenter, you can buy a warranty that covers it completely including tax for very reasonable prices.   If something goes wrong, they give you a gift card with all of your money back. 

[Ram 2 GB]

3 hours ago, toysniper said:

It happens, Sorry to hear your GPU died.  What were you using?    Pro tip if you buy from Microcenter, you can buy a warranty that covers it completely including tax for very reasonable prices.   If something goes wrong, they give you a gift card with all of your money back. 

Sapphire nitro+oc Rx 4804GB, and i live in indonesia. So no Microcenter and no extended warranty