My system has two 256 mb memory sticks:  DDR2 SDRAM, PC2-5300, 667 mhz, CL=5, 1.8 V, unbuffered, non-ECC

Can I replace them with two 1 GB memory sticks from Crucial:  DDR2-800, SODIMM,  200 pin, PC2-6400, CL=6, 1.8 V, unbuffered, non-ECC?

or does different CL values (5 vs 6) and PC2-5300 vs PC2-6400 make the proposed upgrade memory non compatible for use on my INSPIRON 6000 PC?