can i mix server ram?

[dreamcast4599]

so a few weeks ago i picked up a used Supermicro X9DRi-LN4F+ V1.20A with two 10 core cpus and 32 gigs of ram 4 8 gig sticks not sure of the speed im gonna assume its ddr3 1333 but i cant be sure since im not home i have several stick of 4GB ddr3 pc3 8500 both the 8gig sticks and 4gig sticks are ecc registered ram can i mix them in my server or will it cause issues? i know ram will downclock to the lowest speed but i am unsure if i can mix 4gig and 8gig sticks together nor am i sure if the ranks of the ram matter as i know some server ram comes in 2 rank 4 rank 8 ranks etc

one more thing if i have say 4 8gig sticks with 8 ranks can i mix them with 4gig sticks that have say 2ranks or 4 ranks?

heres a link to the mobo i bought in case it helps Supermicro X9DRi-LN4F+ V1.20A LGA 2011 X79 FW Updated Includes CPU 1 Year War! | eBay

[Somerandomtechyboi]

Server needs ecc ram, if yours isnt ecc then its not gonna work

 

Mixing capacities does work but its usually abit more sketchy than just mixing ram kits/ics

[SupaKomputa]

since you have it already, why don't you just try it.

and run memtest86.