I made a program that is sends data every 250~ ms.
I saw problem after 400 < 550 bytes(Sorry I didnt count).
After 400 < 550 bytes the Wiz module skips sending byte to tcp server or clients.
A tried 1.6.8 - 1.6.9 FW and the problem is same. But I tried 1.6.4 and It is working well.
So I think newer fws have problem.
I attach pictures about settings, and the problem, and when working well with 1.6.4 fw.