a 3200+ venice at 2.7 will not really give you much performance advantage over a 3700+ SD at 2.6. In fact, it may actually give slightly lower performance because the Venice has half the cache. To get better performance out ofthe Venice you'd probably have to get the 3200+ to 2.8+
if you want to reach higher than 2.6Ghz you would be best off getting a better stepping 3700+ SD, opteron 146 or 148, or get a dual core. the dual core opteron 165's almost all get to 2.6Ghz without problems. Then it would be like 2 of your cpus put together