SSL ciphers difference

I am looking at the difference of these ciphers after I run
openssl ciphers -v

DHE-RSA-AES256-SHA      SSLv3 Kx=DH       Au=RSA  Enc=AES(256)  Mac=SHA1
DHE-DSS-AES256-SHA      SSLv3 Kx=DH       Au=DSS  Enc=AES(256)  Mac=SHA1
AES256-SHA              SSLv3 Kx=RSA      Au=RSA  Enc=AES(256)  Mac=SHA1


As it states, they are all used in SSLv3, encryption is AES(256), and Message authentication codes is SHA1

the DHE-xxx use Diffie-Hellman (need authentication) key exchange, but the AES256-SHA uses RSA (both digital signing and encrypting data) key exchange. The Auth difference between RSA and DSS (Digital Signature standard). Verify the DSA a little bit slow.