One out of the 4 dimms was faulty.
Having been able to reproduce the issue on other machines I reported to the vendor requesting a replacement.
The vendor was not prepared to send replacement, asking instead to either send the faulty Dimm back or the full order.
A refund would be provided if/when the item arrived in China (postage and Label at my cost)
Clealry seller not testing these modules and relying on buyers finding shipments to China too much hassle..
well done! Keep your refund