Loan Deferment and Early Repayment?

[IRdreams]

My loans are all subsidized and currently in deferment due to my status as a grad student. However, I really dislike being in debt and am bad at long term savings. I've also had a bit of a windfall and have the cash on hand to payoff a portion of the principle. What will happen to my deferment status if I do payoff a bit of the loans?

I will still be in grad school for at least another 3 years and would like to have deferment remain in effect, but I'd like to get some of the debt down especially while its is not accruing interest. I know the most logical plan would be to save money and accrue interest on that and pay them off in one lump, but with my savings patterns that seems unlikely.