Hi, thanks for the information. Unfortunately it's made your thread so long I can't look at it when I'm on my phone (which is when I do most of my Tom's Hardware-ing)
I've taken the relevant information out and pasted it below so could you do me a favour and delete the contents of your two posts to make the thread a bit more manageable?
Operating System: Windows 7 Ultimate 32-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.141211-1742)
Language: English (Regional Setting: English)
System Manufacturer: BIOSTAR Group
System Model: A55MH
BIOS: BIOS Date: 04/17/12 17:50:52 Ver: 04.06.04
Processor: AMD A6-3670 APU with Radeon(tm) HD Graphics (4 CPUs), ~2.7GHz
Memory: 8192MB RAM
Available OS Memory: 3578MB RAM
Page File: 2430MB used, 4723MB available
Display Devices
---------------
Card name: AMD Radeon HD 6530D
Manufacturer: Advanced Micro Devices, Inc.
Chip type: AMD Radeon Graphics Processor (0x964A)
DAC type: Internal DAC(400MHz)
Device Key: Enum\PCI\VEN_1002&DEV_964A&SUBSYS_17071565&REV_00
Display Memory: 2032 MB
Dedicated Memory: 499 MB
Shared Memory: 1532 MB
Current Mode: 1440 x 900 (32 bit) (61Hz)
Monitor Name: Generic PnP Monitor
Monitor Model: G19LWk
Monitor Id: AOC1902
Native Mode: 1440 x 900(p) (60.731Hz)
Output Type: HD15
Driver Name: aticfx32.dll,aticfx32.dll,aticfx32.dll,atiumdag.dll,atidxx32.dll,atiumdva.cap
Driver File Version: 8.17.0010.1333 (English)
Driver Version: 14.501.1003.0
DDI Version: 11
Driver Model: WDDM 1.1
Driver Attributes: Final Retail
Driver Date/Size: 11/20/2014 22:44:14, 1127496 bytes
Drive: C:
Free Space: 443.3 GB
Total Space: 476.8 GB
File System: NTFS
Model: WDC WD5000AAKX-753CA1 ATA Device
If your CPU is only at 21% when you're watching a video then the CPU isn't the problem and as it's an APU, the built-in graphics are more than capable of running a video.
This leads me to suspect it's a software issue. How long ago did the problem with stuttering begin? Have you tried a different browser?
Download, install and run the program Malwarebytes and fix any problems it encounters www.malwarebytes.org
Check the health of your Hard Drive using a program like Crystal Disk Info
http://crystalmark.info/software/CrystalDiskInfo/index-e.html
And get back to me with what you learn from all this and we can take it from there