Evaluate the speed of the algorithm GCM AES-128 and compare it whith speed of one of the stream chipher in eSTREAM. Can someone give such an assessment?
eBACS, as given by CodesInChaos, is a great resource, and it provides much more data than I could hope to give in this answer. However, the page is not explicit about whether or not AES-NI was used — looking at the results, it doesn't seem so.
For an extremely shallow analysis, but allowing us to know for-sure about hardware acceleration, we can use the command-line tool
So, on my system (which has an Intel i5 Ivy Bridge and thus the AES-NI instruction set), AES-GCM processes data at about 1.34 GB/sec while Salsa20-256 with HMAC-SHA1 only manages 0.30 GB/sec.
However, it's thanks to the aforementioned AES-NI instruction set that AES-GCM fares so well.
Note here that Salsa20-256 with HMAC-SHA1 outperforms AES-GCM. So, if your requirements allow you to use the AES-NI instruction set (e.g. the near-latest Intel chips), then AES-GCM is definitely the way to go. On the other hand, if your specs are more modest, you may want Salsa20-256 with HMAC-SHA1.
Another benchmarking tool is