Anyway I managed to put all the cards to p0 state also in windows. It is the same "trick" as in linux using nvidia-smi tool.
I'm not responsible if You kill Your GPU. The risk is Yours.
The procedure is:
1) open cmd.exe with the admin privileges
2) cd C:\Program Files\NVIDIA Corporation\NVSMI
3) nvidia-smi -q -d SUPPORTED_CLOCKS -i 0
4) nvidia-smi -ac 3505,1455 -i 0
-i 0 means display adapter 0. -i 4 would mean display adapter 4.
Step 3 is used to show the possible clock settings combination for each power state. The numbers will change if You overclock Your gpu before running step 3.
The result after typing step 3 would be looking like that:
C:\Program Files\NVIDIA Corporation\NVSMI>nvidia-smi -q -d SUPPORTED_CLOCKS -i 0
==============NVSMI LOG==============
Timestamp : Sat Jan 02 19:09:48 2016
Driver Version : 359.06
Attached GPUs : 5
GPU 0000:01:00.0
Supported Clocks
Memory : 3505 MHz
Graphics : 1635 MHz
Graphics : 1623 MHz
Graphics : 1610 MHz
Graphics : 1598 MHz
Graphics : 1585 MHz
Graphics : 1572 MHz
Graphics : 1560 MHz
Graphics : 1547 MHz
Graphics : 1534 MHz
Graphics : 1522 MHz
Graphics : 1509 MHz
Graphics : 1496 MHz
Graphics : 1484 MHz
Graphics : 1471 MHz
Graphics : 1458 MHz
Graphics : 1446 MHz
Graphics : 1433 MHz
Graphics : 1420 MHz
Graphics : 1408 MHz
Graphics : 1395 MHz
Example:
nvidia-smi -ac 3505,1446 -i 0
The nvidia inspector shows Your card in p0 and You can overclock also the memory with msi afterburner or any other oc tool.
If You type nvidia-smi -ac 3505,1440 -i 0 it won't be accepted because 1440 is not in a list of matching Mhz for memory clock 3505.
I'm not responsible if You kill Your GPU. The risk is Yours.