Asus "DIMM Fit" BIOS Utility Issues

[mgilbert]

I have an Asus X870 TUF Gaming ATX motherboard running the latest BIOS. I also have a Corsair 64gb (2*32) 6600 MT/s CL32 DRAM kit. It's not stable at 6600, but is at 6400-CL32, or better yet, 6000 with 30,36,36,76 timings. The RAM is XMP, so doesn't have EXPO settings, so I used DOCP1 to overclock the RAM, and set the main timings manually.

The board has a feature called DIMM Fit (DIMM Fit Pro), which is supposed to optimize all the RAM's settings, including timings. It takes several hours to run. I ran the simpler DIMM Fit (non-Pro), and it completed successfully, after over six hours, but it changed nothing that I could find in the way of timings, and several memory benchmark runs showed no difference in performance.

So, I decided to try DIMM Fit Pro. It has twenty or more settings, but all but five are labeled "N/A", and are set to "0", and cannot be changed. The five it does have are voltage settings. So, all the timings options are apparently not available.

What am I doing wrong???

[Silent_Scone]

Hi @mgilbert

DIMM Fit will test variance values for drive strength/impedance settings to help find better stability. However, at 6600MT/s you're limited by the capability of the CPU's IMC whilst at 1:1 UCLK.

6400, if stable, is a good place to be. How are you testing stability?

[mgilbert]

To test stability, I run several different stress tests, each for a few hours - OCCT, MemTest86, Prime95, etc.  I thought I had the system stable at 6400 MT/s with a 1:1 UCLK.  It passed hours upon hours of everything - until I ran Prime95, and it failed within minutes!  My system won't run at 6600 under any circumstance.

I decided to just stick with 6000 MT/s, which automatically runs the UCLK at 1:1.  I adjusted the timings for the lower clock speed, based on the XMP table.  At 6600, it calls for timings of 32,39,39,76, but at 6,000 it is stable at 30,36,36,69, which is quite good.

I don't think I'd gain much of anything with further tinkering, and I'm tired of messing with it.  It's rock solid stable at those settings.

[Silent_Scone]

I personally wouldn't use any of those to test memory. Use Testmem5 or Karhu RAM Test, these are memory centric stressers. Memtest86+ is great for finding faulty modules, but not so much for outright OC instability where things are less conditional.

You'd be right in thinking that way. Not many CPUs will do 6600MT/s 1:1 unconditionally, and when it's possible there's usually some compromise.

Memory Overclocking

[mgilbert]

TestMem5 is one of the utilities I use.  I just forgot to mention it.  Interestingly, it's also one of the tests my system passed when set to 6600 and 1:1.  The only one that threw errors was Prime95's large data set test.  Strange...  Usually OOCT's memory test catches issues before anything else, but not this time.

[Silent_Scone]

I honestly wouldn't worry too much about Prime95, that's why I suggested not using it. Not only is it a power virus, but it's not always obvious what subsystem the instability is coming from.

[mgilbert]

Oh, okay.  Thanks for the information.