HIgh CPU usage after upgrading to SSD in Sony VAIO S13

I recently upgraded the primary hard disk in my laptop Sony VAIO S13 (SVS13137PNB) from a HDD to SSD (Samsung 850 EVO). The HDD (Toshiba) was then loaded into a 2nd Hard Drive Bay Caddy ( http://www.storite.in/productdetail.php?c=21&p=90) to replace the laptop's CD drive with this hard disk. The laptop right after that booted from the old hdd which was in a new position in the laptop. Next step was to clone or reinstall the Windows 8 into the new SSD from recovery I had already made. This migration/reinstallation turned out to be a nightmare for one week, after which I eventually got my windows 8 into the SSD with no OS inside the old HDD.

However a new problem turns up that my CPU usage is always about 40%. I hoped that after the free upgrade to Windows 8.1 and a thorough antivirus scan, this problem might disappear. But alas, it is still there. On the task manager, it shows system always hogging on 24% of CPU while SYSTEM interrupt another 10%, which along with the other processes always consumes a constant 40% of CPU @ 0.45GHz higher than its normal frequency all the time. The result is that the computer fan runs at full speed to dissipate excessive heat and drains the battery very fast.

On the internet, others have faced this problem because of an outdated bluetooth driver or a power cable issue. In my case, I have uninstalled the bluetooth driver and even this problem persists. The system interrupt process indicates that certain hardware interrupts the functioning of the system such as a mouse movement or keypad, but in my case it is constantly very high. I suspect that it could be because the new hard disk is constantly interrupting the CPU. Can anyone help diagnose this problem? I am worried that in this manner the CPU will degrade at an accelerated pace, let alone the fact that it makes the laptop slow while using other CPU intensive programs.

 

Try Process Explorer. https://technet.microsoft.com/en-in/sysinternals/bb896653.aspx Don't do anything rash - just observe.

What is your activation status? Maybe it is trying to make sure your Windows is genuine.

Frankly, I have a dread of upgrades to existing Windows installations. I would much rather do a clean install of the OS after a major hardware change rather than try to fix the problems caused by the upgrade.

 

The Windows is activated. I do not know how to use the process explorer very effectively. What I want to see is what exactly is interrupting the processor so frequently. I think the system process (NT kernel and system) is also working on that at the kernel level. This is where I want to sniff out what is hogging on my CPU. I checked my suspicion that the old HDD in another slot is possibly causing the problem by disabling that hard disk from the device manager only to see that the problem still persisted, which eliminates that possibility.

I made the following observation that when I opened my laptop with a battery of 50% without external power the CPU usage was much lower at about 10%. When I reconnected the power cable, it again shot up to high CPU usage and never came back when, e.g., I disconnected the power.

The last resort to me seems a fresh recovery of windows 8, not to mention that all this happened after a fresh Windows recovery in the new SSD. I use the laptop very extensively for my work, so something like that right now is very inconvenient and a diagnostic troubleshooting is much more desirable. Please help.