bakarg :
Thanks for your help,
Let suppose
if E7 8890 V3 official CPU Frequency is 2.5G
than Engineering Sample ( E7 8890 V3 ES) CPU Frequency can be 2.4 GHz ?? Or must be 2.5 GHz ?
It could be 2.5GHz, or it could be 2.4GHz or lower, it depends on the Engineering Sample you get. Even if you're getting the ES at a discount there are risks to it, like motherboard compatibility problems, lower clockspeeds due to stability issues during the earlier stages of development, or other problems that got ironed out in later stages of development eg. crashes when executing specific code or performing specific calculations.