Laptop I was dealing with had 960GL motherboard; so 553MHz chip was needed which was out of stock. So I ordered 667MHz and yes, it works just great. Don't underestimate this product for the price tag; RAM is seated smoothly and the initial lags of 1 GB RAM are no more there. Currently running Win10 and 1.2 GB RAM is used. Yes, I have virtual RAM more than 1520 GB, still, have them in pairs is the best way to operate the system. My other RAM is Kingston 800 MHz at 1.9V. But they both are working fine. I truly appreciate this product from Simmitronics.

A K Patil