Thread Subject: sparse matrix and pcg()

Hello,
   I solved Ax=b, A is large(of size 2e5), sparse(each row has no more than 26 nonzero), symmetric positive definite matrix. I did it in two ways,
1) L=chol(A,'lower'); tic, x=L\(L'\b),toc;
2) tic,[x,flag,resrel,iter]=pcg(A,b,[],n,[],[],x0),toc;

L is dense, iter=6. So theoretical 2) should be must faster than 1). But 1), 2) ends up with the same time.
Why?