After testing a first strip 4GB which I was satisfied, I ordered a 2nd order to be "dual channel" on a motherboard Asus P8B75-M. There: bad surprise as impossible to boot the PC with the faulty module. Which I replaced without discussion by Amazon. After receiving the new strip, everything is back to normal and the test with the command "winsat mem" gives a performance of 20.8 GB / s. Note that the motherboard tops out at a 1600 MHz bandwidth and does not natively test this RAM maximum of its possibilities I still removes a star because there is doubt about the quality control. Aesthetic is successful and the heatsink trust.