They are the same and maybe the ds3h came out earlier than the hd3. Get the lower price one. By the way what CPU do you have?
I add the link for comparing. http://www.newegg.com/Product/Productcompare.aspx?Submit=ENE&N=100007627%2050001314%20600315497&IsNodeId=1&bop=And&CompareItemList=280%7C13%2D128%2D582%5E13%2D128%2D582%2DTS%2C13%2D128%2D547%5E13%2D128%2D547%2DTS&percm=13%2D128%2D582%3A%24%24%24%24%24%24%24%3B13%2D128%2D547%3A%24%24%24%24%24%24%24