These modules have obviously not been tested at the factory. I ordered 3 kits (six 4GB modules in total) and found that 2 of the modules were defective. One module failed memtest, and the other module was not recognized when inserted (in fact when this module inserted, the whole bank went dead and was not recognized). Confirmed by replacing with working modules.
Unless you have the ability, time and inclination to thoroughly test and troubleshoot memory, I strongly suggest avoiding these, despite the attractive price. I guess you get what you pay for.