Upgrading RAM (For new Build), do I use my old ones as well?

[Memesnthat]

I have 2x8 incoming:

Corsair Vengeance RGB PRO 16GB (2x8GB) / 3200MHz / DDR4 / CL16

 

But I also have 2x8:

Corsair Vengeance LPX Black 16GB (2x8GB) / 2666MHz / DDR4 / CL16

 

Just lying about from my old build. My question is: Do I pop the old ones in as well in the 2 ports left over or do I simply just discontinue them and stick with just the 2 faster ones? Can't really find a great way to form this into a google search and was curious about your thoughts if this could impact performance or if it wouldn't prioritize the faster memory etc.

 

Thanks.

[mail929]

If you would be running out of RAM with just the single set, sure, but otherwise that's a significant speed drop because all RAM will run at the lowest stick's speed.

[dgsddfgdfhgs]

2 minutes ago, Memesnthat said:

Corsair Vengeance LPX Black 16GB (2x8GB) / 2666MHz / DDR4 / CL16

test max OC you can get with 2666 kit, if you can reach 3000+mhz you shall use both kits at your OC settings, but you may not ever utilize 16g ram capacity, depend on what you do

[KarathKasun]

1 minute ago, dgsddfgdfhgs said:

test max OC you can get with 2666 kit, if you can reach 3000+mhz you shall use both kits at your OC settings, but you may not ever utilize 16g ram capacity, depend on what you do

Not quite.

 

If the chips on the modules are different, the sub timings will be different and you will need to blow out the timings by a huge amount.  On Ryzen this will make the system slower if you never use more than 16gb of ram.

[Wormhole]

if its ryzen sell the old ram and save for a 3200 kit with the same timings, from my experience 3000 or less is pretty damn slow