Both 10TB models are 5400 rpm, 14TB is 7200 rpm. Ran both speeds in a single RAID array without issues though.
Added SMART data from one drive for each model.
Bunch of random things for sale, used and fully working unless stated otherwise.
Misc
Google Pixel Buds Pro - Porcelain - Sold ($75)
HDDs
2x 14TB WD HDD (WD140EDGZ) - Sold ($105/each)
8x 10TB WD HDD (WD100EMAZ) - Sold ($75/each)
6x 10TB WD HDD (WD100EZAZ) - Sold ($75/each)
Shipping to US...
Could be timing/speed related, as Areca specifies only 1200MHz is supported at 8GB. I'm also running a stick of ADDE1333W8G9-BMIE and have the full 8GB showing up. Don't have any way of checking supported timings on this stick unfortunately.
If it helps, CDW seems to have the Transcend stick...