[SOLVED] tRFC not matching in HWINFO versus UEFI ?

[ajay12131]

Hello everyone. I recently upgraded my RAM to 2 x 16GB @3000mhz (mismatched sticks) and managed to run them in dual-channel @3600mhz. There is no stability issue yet (over 1 month of usage).
However, I recently noticed something called tRFC 990 (I am a newbi to oc) in HWINFO summary. I looked at Google for info and found that 990 is too high for tRFC. So I tried to lower it manually from BIOS, but there is no 990 at all in the BIOS DRAM Timings.

As displayed in the pictures UEFI has tRFC - 312, tRFC2 - 192 and tRFC4 - 132
As an absolute noob, I have no idea how HWINFO is calculation it to be 990.

Please guide, what are these values and how do I calculate tRFC
And should I even tweak something here or just let it stay as it is?
Thanks.

 

[kerberos_20]

obviously your uefi shows you incorrect readout, hwinfo shows tRFC cycles (not value in ns)

rfc depends on what IC you have, if you have mixed IC, than that can limit your lowest value aswell, most ICs can run around 300-350ns
so your 990 cycle value is rather high

at 3600 MT/s, tRFC set to 630 has latency of 350ns which is typical value for most ICs

samsung B-die is probably the only one which can run it below 200ns
how to calculate?
tRFC time (ns) = cycles * (2000 / DataRate)
tRFC2 = tRFC / 1.346
tRFC4 = tRFC2 / 1.625

now fill in your values:
tRFC 550ns = 990 * (2000 / 3600)

you could start with tRFC set in uefi to 630 and then going down, every 18 cycles reduces 10ns, reduce as much as you can (with your tRC at 68, 545 is probably lowest you could go)
if you want to go even lower, then you would need to reduce tRC timing

 

[ajay12131]

Thanks @kerberos_20 for the helpful reply. As you said, the UEFI was displaying incorrect tRFC information at AUTO. And as per your suggestion, I first set it to 550 and it worked. So I tried lowering it further down to 545 as you mentioned and it still worked. Not to mention I also applied the formula to calculate tRFC2 and tRFC4 respectively and now the values are all same in HWINFO as well as UEFI.

As you said in order to lower it even more, I may need to lower the tRC timing as well. In that case I want to tell you that the system is allowing me to set tRC down to 55. But would you suggest me going that down? Would I notice performance boost or it will just be a trial and error matter?

Thank you for replying. my regards.

 

[kerberos_20]

Thanks @kerberos_20 for the helpful reply. As you said, the UEFI was displaying incorrect tRFC information at AUTO. And as per your suggestion, I first set it to 550 and it worked. So I tried lowering it further down to 545 as you mentioned and it still worked. Not to mention I also applied the formula to calculate tRFC2 and tRFC4 respectively and now the values are all same in HWINFO as well as UEFI.

As you said in order to lower it even more, I may need to lower the tRC timing as well. In that case I want to tell you that the system is allowing me to set tRC down to 55. But would you suggest me going that down? Would I notice performance boost or it will just be a trial and error matter?

Thank you for replying. my regards.

you should probably run memtest

 

[ajay12131]

you should probably run memtest

Greetings @kerberos_20. I'll run memtest and post the outcome here. Thanks for your guidance. Much appreciated.

 

[ajay12131]

Hello again @kerberos_20. Running MemTest found errors and I started from the very beginning as you suggested, tRFC = 630 and the system was quite stable there. So I tweaked certain values and now the system is running at tRFC = 612.

MemTest86 found ZERO errors in all tests for 2 complete cycles.
I'll try to test lower possibilities and inform here if succeeded.

Big thanks to you once again for your time and valuable guidance. My regards.