Disk storage of RSA and DSA keys
Yes. There is a difference between key strength, key size and the size of the encoding of a key.

The modulus of the RSA private key determines the key size, for instance, but an RSA key commonly also contains the public, private exponent and CRT parameters, an encoding structure etc. etc.

In GPG indeed the "key" consists of many additional parts as well (as you can see from the size). You can packet-inspect the keys in GPG by simply performing gpg &lt;exported-key&gt;.

See here for more information (and note that the question really belongs on Superuser, but whatever).