4 RAM sticks - worse benchmark results than with 2 sticks normal?

[bjorn.sveding]

In my Asrock Z370 Extreme4/8700K-system I've been using 2* 8 GB stick of G Skill Flare X 3200 RAM. Now I've upgraded to 4 sticks of that type.

All the primary timings and speed and voltage for the RAM are set to the same values as before the upgrade, but I notice a 2% drop in performance if I run Cinebench 15 multi benchmark (1600 instead of 1630 for my OC CPU).

Does this seem normal? I'm aware that 4 stick of RAM could mean problems reaching the same optimal settings, but since I in fact are using the same settings now should I really have this situation?

 

[jgustin7b]

Just make sure the ram are in the correct slots as said in the motherboard manual. Knowing you have 4 sticks, the ram should be alternating. Ram a, ram b, ram a, ram b....unless they are all identical.

 

[SkyNetRising]

4 RAM sticks - worse benchmark results than with 2 sticks normal?

Yes - it's normal.
Going from 2 modules to 4 modules on a dual channel motherboard requires command rate setting to be increased from 1T to 2T. This causes slight memory performance decrease.

 

[bjorn.sveding]

OK, but my motherboard favored 2T even before going to 4 modules. It's a bit odd, but I never changed that. So it's 2 before and after. I tried changing to 1, but then it refuses to boot.

I'm running 4000 MHz/17-19-19-39/1.35V on the memories by the way. So it's that configuration I've compared. Other configurations yield lower results and the 4000 one is the one I'm familiar with and know the results before and after.

 

[bjorn.sveding]

Just make sure the ram are in the correct slots as said in the motherboard manual. Knowing you have 4 sticks, the ram should be alternating. Ram a, ram b, ram a, ram b....unless they are all identical.

Well, they are all identical...

 

[SkyNetRising]

With 2 modules you could run them in 1T command rate mode. With 4 modules it's no longer possible.

 

[bjorn.sveding]

With 2 modules you could run them in 1T command rate mode. With 4 modules it's no longer possible.

Like I wrote before - they were running in 2T command rate both before and after.

But I'm beginning to suspect second and third timings could actually make this much of a difference. I had all these on auto in the BIOS and when looking TRFC it now is 840 and that seems higher than it was before. So I'll guess I'll try and tweak it a bit.

One alternative explanation could be that, even if CPU-Z and other displayed command rate as 2, the system actually used CR1 now and then when running just two sticks,

 

[Calvin7]

Memory is guaranteed in the form it is sold in not by matching up part numbers. Adding extra memory, regardless of brand and model number, will increase stress on the memory controller. As a result the memory may no longer be able to operate at rated specifications and/or the PC may not boot up.

Since the old memory has never been tested with the new memory there are no guarantees it will work or how it will work if it does.