We already mentioned that QX6850 quad core extreme at 3 GHz and FSB 1333 will cost a saucy $999. E6850 dual core with 4 MB cache, FSB 1333 and the same 3 GHz clock will cost $266 or almost four times less. Dasd
E6750 dual core with 4 MB cache, FSB 1333 and 2.66 GHz clock will cost only $183 while E6550 dual core with 4 MB cache, FSB 1333 and 2.66 GHz clock will be introduced at at $163. The E6540 has the same specification and will cost the same, but it won't have Intel TXT. TXT in this case stands for Trusted Execution Technology.
According to Intel's website "Intel Trusted Execution Technology provides hardware-based mechanisms that help protect against software-based attacks and protects the confidentiality and integrity of data stored or created on the client PC. "
It is suppose to help you be safer in this nasty world. This prices will be effective on the 22nd of July unless Intel decides to launch these CPU's earlier.
You can learn more about TXT here 70 KB PDF.