intel speedstep issue

actually i had changed my AC adapter, but i get an original one  with the same specification, V & W.

i know disabling Speedstep looks the system on low, but on at least on source monitor it works on 2.3GHz with and works 100% not likely when speedstep is on, works on 0.76GHz 

Disabling Speedstep will lock the system into low power battery mode all the time.

Does the system correctly recognize the AC adapter (F2 at powerup to check)?

No no, it works fine  :))

The question is - is the replacement adapter correctly identified by the system, or does it show unknown - or intermittently lose the connection?

If the AC adapter shows unknown, the system will run as if on battery all the time.

Well as dell website offers drivers I installed. There is no chip drivers on dell website. Even sound driver dose not work, I work on driver from Microsoft update, the same for wireless driver is sux too. But all drivers are fine. Dell offers video driver, sound, WiFi,  Wan, another other dell software. Drivers like win 7 dell dose not offer

In your first post, you mentioned clean installing Windows 8.1.  Now you mention Windows 7.  What system model is this (i.e., Inspiron N5110, XPS L502x, etc.) and exactly which OS (7 or 8.1) and which version (32-bit or 64-bit) have you installed?

When you installed the operating system, did you install the chipset drivers afterward?

Lol, well I have now win 8.1 x64 .. the support for window 8 comper to win 7 is so poor. Few drivers for win 8 on dell website. I have dell inspiring n5110 .

8.1 isn't supported on this system, but I suspect another cause - this is a relatively old system now, and if it's never been cleaned out (i.e., dust removed from the heatsink and new thermal compound applied to the CPU/GPU heatsinks), it's well past time for that.  The system is likely overheating and causing the throttling you're seeing.

Unfortunately, accessing the parts you need to clean means a total strip down of the system due to its design:

Service manual is here:

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The mainboard has to come out of the system to access the parts that need maintenance.

Once the GPU/CPU is re-pasted and the dust is cleared, the system will likely run much cooler and the throttling will cease.

well i give up, i just installed Win 7, all drivers are fine, the internal parts are clean, i just cleaned it not so far from now, temperature are fine dose not go above 60, 2 minute on windows logging the CPU works fine, but it goz down after that. i checked with the intel utility it gave me this info:

Intel(R) Processor Identification Utility
Version: 5.30.20150729
Time Stamp: 2015/09/20 23:58:27
Operating System: 6.1-7601-Service Pack 1
Number of processors in system: 1
Current processor: #1
Active cores per processor: 2
Disabled cores per processor: 0
Processor Name: Intel(R) Core(TM) i5-2410M CPU @ 2.30GHz
Type: 0
Family: 6
Model: 2A
Stepping: 7
Revision: 1B
Maximum CPUID Level: D
L1 Instruction Cache: 2 x 32 KB
L1 Data Cache: 2 x 32 KB
L2 Cache: 2 x 256 KB
L3 Cache: 3 MB
Packaging: µPGA/BGA
Enhanced Intel SpeedStep(R) Technology: Yes
MMX(TM): Yes
Intel(R) SSE: Yes
Intel(R) SSE2: Yes
Intel(R) SSE3: Yes
Intel(R) SSE4: Yes
Intel(R) AES-NI: Yes
Intel(R) AVX: Yes
Enhanced Halt State: Yes
Execute Disable Bit: Yes
Intel(R) Hyper-Threading Technology: Yes
Intel(R) 64 Architecture: Yes
Intel(R) Virtualization Technology: Yes
Intel(R) VT-x with Extended Page Tables: Yes
System Graphics: Intel(R) HD Graphics 3000
Expected Processor Frequency: 2.30 GHz
Reported Processor Frequency: 0.79 GHz
Expected System Bus Frequency: 100 MHz
Reported System Bus Frequency: 100 MHz
*************************************************************

i have been reading so much titles on the internet about this issue, no real or clear solution.

maybe the main board is get tired