Question about a10 7890k support for 32G on A88M-G

[xinminglai]

Hi, Just curious, Anyone here knows wether a10 7890k supports 32G memory at 2133 please?
Here, I got a pair of 16G F3-2400C11-8GSR*2 3 years ago, and used for a while, For now, It was running stable always.
Last week I wish to upgrade my system to 32G memory,
So, I bought another pair of same memory. But the system doesn't run stable as I think.
Then I test the memory with memtest86+, I found There will be memory errors reported when all 32G installed to the system.
But when I test 16G memory separately (both new and old or mixing old with new), They all pass the test. If I install them all together, There will be errors reported.
Someone told me that I can ask here for help. Because maybe I need to tweak some timings.
Any ideas?

BTW. The memory settings I tested are
10-12-12-28 @1.6v (1.61v/1.62v/1.63v/1.64v)

Thanks!

[emissary42]

Did you test your 2x8GB configurations in both the recommended and the alternate memory slots?

It might an issue with the other slots/memory training for those is too weak for DDR3-2133. Also the APUs integrated memory controller is rated a lot lower when used with four modules vs just two. So it could be either a MB or a CPU issue. Things you could test is raising memory and/or MCH voltage or manually relaxing some of the secondary timings a bit. If you can't get it to work, i would test for DDR3-1866 next.

[xinminglai]

Yes, Actually, I found, that when 2 memory will *always* work,
If I have more than two, There will be problem.

[emissary42]

Well if two modules work just fine in either slot 1+3 or 2+4, then i would guess the issue is not on the board but more on the CPU side of things (weak IMC). In that case slightly raising the voltage for the memory controller might help.

Adding a bit of Vdimm helps when the memory VRM is weak and voltage drops quite a bit under load.

On the timing side you could try to set command rate 2T, raise tRRD (up to 8), tRFC (max), tWCL (9 or 10).

[xinminglai]

Thanks, I think it's because of a10-7890k, the memory controller can't work at 2133 with 32G ram. I lowered the frequency to 1866, It works fine.