Intel Turbo Boost..Can boost up to 3.7GHz on all cores, or per core, of an i5-2500 depending on the workload and other factors of the active cores..Also depends how you have it set in the BIOS, auto per core or manual all cores..Only way you'll OC is by raising the BCLK, and you can't raise it very much, if at all, depending on the mobo..If your mobo (whatever it is) has a Dummy OC, Level Up, OC Tuner or similar feature, best just to use that..Software like AI Suite (Asus only) can do it to.

You're welcome, but it's impossible for anyone to tell you without knowing what mobo you have..What is the make/model of your mobo?..Can you provide a link to the online manual for your mobo?

Ai Tweaker -> Ai Overclock Tuner: Manual
Ai Tweaker -> BCLK/PCIE Frequency: 100
Ai Tweaker -> Turbo Ratio: By All Cores (Can Adjust in OS)
Ai Tweaker -> By All Cores (Can Adjust in OS): 37
Ai Tweaker -> CPU Power Management -> Enhanced Intel SpeedStep Technology: Enabled if you want the CPU to downclock at idle and scale up depending on load or Disabled if you want to run at 3.7GHz all the time.
 
You can set Ai Overclock Tuner to X.M.P. (which would be better) instead of Manual if your RAM has an optimum profile to select from, otherwise, in Manual you can choose the correct Memory Frequency and DRAM Voltage then set the Primary Timings in DRAM Timing Control.
 
As I said before, without a K (unlocked multiplier) series CPU it's probably best just to use OC Tuner in BIOS and let your mobo go thru it's rountine of automatically setting everything to the optimal performance settings..Or use the Auto Tuning feature in AI Suite to Level-Up.
 
Get Intel Burn Test to stress the CPU and watch the frequency in CPU-Z. 

There's really nothing to it..Go into the BIOS in the Ai Tweaker screen and make the changes in my previous post..Or..Select OC Tuner, then click OK and your PC will reboot a number of times (2,3,4 maybe) while auto-finding the optimal settings for you..Or..If you have AI Suite II installed, click on Auto Tuning and select the Level Up option you want..You can always return to the stock default settings by pressing F5 while in BIOS, or clearing CMOS with the jumper..Everything is explained in your mobo manual, read it all.
 
There's some ROG overclocking and BIOS guides here..While not exactly the same as your BIOS/mobo, they  are similar enough and the basics are the same..Check the Z77 UEFI BIOS Guide and the 4.4GHz 2500K Overclock Guide..You won't be able to OC your CPU much at all like I said, only with BCLK, but the guides can tell you what's what and how stuff works.

so i tried your approaches, but manually it didn't work bc i coudln't change the multiplier, 2500 is really locked. OC tuner didn't give much, so i went back to the EZ screen and just clicked on turbo picture (duh) and on the EZ bios it shows a clock of 3.452 ghz. then i opened cpu-z during bf4 and it showed from 3.9 to 4.1 ghz speed! is that really what the 2500 is doing? it also said 4 cores on the bottom right of the app. system op showed 45% cpu usage, but mostly mid 30s on BF4. 
 
in other words, is this the turbo function, is the cpu at near 4ghz speed on all 4 cores, and is it giving 45% of its capacity? and this is with 16GB ram and 570Sli. thus i can conclude that this cpu woudl not bottleneck a 970+570(physx)..? that was my only worry. what do you think?
 
thanks for your help!
 
j