Question about Ram RGB Corsair Vengeance RGB Pro 16GB (2x8GB) 3600MHz C18 CMW16GX4M2C3600C18 AND CMW16GX4M2D3600C18

[bosure]

Hello , I got two types of rams actualy when I bought it I did not see the difference. 
I bought  2 x CMW16GX4M2C3600C18 and 2 x CMW16GX4M2D3600C18  rams of  Corsair Vengeance RGB Pro 8GB .

My mother board is an MSI pro carbon wifi X470 and my processor id AMD ryzen 7 3700X. 

Actualy my computer is running fine at low speed, all the ram are working. But when I try to enable the xmp or boost to the high speed 3600MHz,  it cause trouble
(application crash , computer did not boot ...).

I would like to now if the difference may cause the issue ?  If this "letter" is the root cause of the issue ? 

What should I do to enable a better speed ? 

 

 

[c-attack]

That letter indicates a different version, which could include a number of changes from origin to voltage to different timings.  A quick search of the product numbers reveals two kits with two different sets or primary timings.  XMP will never work for that.  It has a different meanings for each kit.  You may be able to run them on manual settings with similar timings, but if those two have different version numbers (3.xx, 4.xx, 8.xx, etc), then I suggest you box one up and send it back.  It's possible to run different ICs together, but for most users this is going to be a crash waiting to happen for the lifespan of your use.