I do own both the Opteorn 6176/6180 (2.3/2.5) as well as an Opteron 6378 (2.4/2.7 ghz)

Due to the nature of the work units all being different lengths etc, I haven't been able to make an exact comparison.

Judging by the points per day they put out, the 6378 probably does a little more work as a total processor, but it has 4 more "cores" so one would expect as much.

As for core for core performance, there's really not much if any improvement on the 6100 series it seems. The 6300 series utilizes shared resources for each core which decreases performance but makes up for it with higher clock speeds generally.

If runtime is important to you it will be beneficial to upgrade as it's all about the number of cores/threads you have.

If going for total points output you will be looking for the most cores at the highest clock rates possible.

If you have the $ for the 6386 go for it. Keep in mind though the 6386 is a 140 watt part wheres the 6380 and below are 115. Doesn't seem like a big deal but when running multiple CPU's 24/7, electric usage does come into play for me at least.

Any specific questions about the processor I can run some specific tests if able. My machines are both running Linux btw.

Edit: Ran the Boinc CPU benchmark and here are the results:

Opteron 6180: 1879 FP, 11895 Integer
Opteron 6378: 1859 FP, 8022 Integer

I should mention the 6180 is in a dual CPU Tyan mb config, whereas the 6378 is running in a single socket Supermicro mb. Not sure if this influences the results in any way. It shouldn't because the benchmark is supposed to measure core performance not total performance.