What is tRC on CPU-Z?

[MyLittleFella]

So, I finally bought more ram for my pc, going from to 8GB to 16GB. (from 2x4 to 4x4). Since the store is sending me the sticks from different distributers, one of them was delivered today. I installed it and everything went fine. Still using XMP, the timings are exactly the same in the BIOS but I came up with this:

On CPU-Z, the tRC from slot #2 is different from the slots #3 and #4. Why is that happening? Is this normal?

(Slot #1 is unassigned cause I'm waiting for the last stick to be delivered).

All of the RAMs are HyperX HX424C15FB/4

 

 

[nick name]

Edit:

 

I understand now.  If you read what I originally posted it may still apply, but in this instance those timings tables aren't showing current timings, but capable timings.  

[MyLittleFella]

1 minute ago, nick name said:

Those aren't different slots, but different JEDEC specs.  It isn't indicating what you're running, but what the timing specs would be at the frequency listed.  

Oh, I didn't know. According to my BIOS information, I'm running on XMP 15-15-15-35.

[badreg]

tRC is row cycle time, which is a secondary timing. It looks like your sticks are not exactly the same, at least when it comes to the XMP profiles. When you buy two different kits, there's no guarantee that the ICs are the same. You can see from CPU-Z that these were manufactured more than 6 months apart.

 

They will still work together, but the 57 tRC kit might not be stable at 55 tRC, so I would recommend putting the 57 tRC kit in channel A, and the 55 tRC kit in channel B. When you turn on XMP, the motherboard will read the profile from the channel A kit, which will be a more conservative setting.

 

Run memtest86 afterward to check for any errors.