I know I'm late to the party, but I wanted to say thanks for this thread. :-)
I was having the same issue. My partition layout was unusual because I had migrated an MBR disk to GPT using gdisk and I put the EFI system partition at the end of the disk. I was not able to activate Intel SRT.
To fix it, I actually moved the EFI system partition to a different disk and expanded the Windows partition to cover the entire drive. After that, Intel SRT turned on with no problem.
Oh Hallelujah !! I'm also very late to this thread and I wish I had found it sooner.. I spent more than a week trying different things trying to fix this issue... Here is a link to a thread from the OCZ forum in case it of any use to anyone.
My system is an ASUS P8Z68-V Pro/Gen3 BIOS 3402
RST drivers 10.8 (see pics on ocz forum for dowce screenshot of my exact settings)
Intel i7 2600k overclocked to ~4500Mhz.
OCZ Agility 3
Seagate barracuda 2TB disk - or 500GB WD blue. - also tried a 2TB WD caviar black but sent it back - (*performance was faulty anyway)
I spent days trying to find a solution - I finally fixed my system thanks to the suggestion by ferhanmm - shrinking and re-extending the volume.. Nothing else worked..
THANK YOU !