Question about default memory speeds for DDR 4

Associate
Joined
27 Sep 2020
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95
I've been having issues recently with my memory configurations since ive upgraded my CPU.

I have 32GB across two sets of 3200mhz rated memory on an x570 motherboard

Corsair Vengeance LPX 2 x 8GB sticks on DIMMs B1 and A1
Crucial Ballistix 2 x 8GB sticks on DIMMs B2 and A2

I cant get the PC to post with these at 3200mhz, which i assume is because i have mixed kits, so they run at 2133mhz default speed.

Next I tried the sets individually. I can get the 16GB Ballistix running ok at higher than 3200, seems to be ok at 3600mhz.
I know i dont really need the 32gb so will probably stick to this and look for a deal on another 16gb set of Ballistix later on. I cant get the Corsair to run at 3200mhz never mind 3600mhz.

My question is that the two sets of supposedly 3200mhz memory show different default speeds in BIOS, the Corsair shows 2133mhz and the Crucial shows 2666mhz? Is there any reason for this..am wondering if this is why i can get the Crucial to run higher, even though they are both supposed to be 3200mhz
 
Soldato
Joined
22 Jun 2006
Posts
5,265
The defaults are usually just to ensure compatibility so that the PC will boot.

In some cases, having a higher default is helpful, because many OEM motherboards don't allow adjustment, so if you were buying it for an OEM PC, the Crucial would run faster than the Corsair. 2666 is the highest official DDR4 and it will usually run fine without adjusting the DRAM voltage, which again is not available in many OEM motherboards.
 
Associate
OP
Joined
27 Sep 2020
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95
The weird thing about the kits is that I could have sworn that i managed to get the mixed kits running at the 2666mhz together on my previous CPU which was a Zen+ 3200g, but cant get it to run on the 5800x. Maybe its a power /voltage thing, and to be honest i cant be bothered with lots of manual tweaking testing and adjusting for the sake of a little adjustment when i wont get a performance improvement in real terms.
 
Soldato
Joined
22 Jun 2006
Posts
5,265
I'd be surprised if you can't run them at 2666, I'd expect at least 2933 to be feasible, though you'd have to set an appropriate voltage (usually 1.35v).
 
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