Overwatch performance problems

Actually, 4GB RAM is quite a bit, when you use it at the intended speed.
Unfortunately, the default power settings dumb-down the possible speed of the computer.

Start> Control panel > look in the upper path bar, click on the arrow ">" after "control panel."
this opens a drop down menu
Then click "All control panel items"
Click: Power Options
Click: Show Additional Plans
Click: The arrow, check the box that says "high performance."
Click: Change Plan Settings
Turn Off Display: Never
Put Computer to Sleep: Never
Click: change advanced power settings
Hard Disk : turn off hard disk after: Never
Wireless adapter Settings: power saving mode Setting: Max Performance
Sleep: sleep after: Never
Allow Hybrid Sleep: Setting: Off
Hibernate After: Setting: Never
Allow Wake Timers: Setting Disabled
USB Settings: selective suspend setting Setting: Disabled
PCI Express Link Power State Setting: off
Display: turn off display Setting: Never (turn off monitor manually if desired)
Multimedia Settings
When sharing media : prevent idling to sleep
When Playing video: Setting: optimize video quality
Now: Click "OK"
Computer> system properties > Now open the Device Manager
Click On: mice and pointing devices ">" click on the arrow
Double Click on HID complaint Mouse
Click: power management tab
UN-check the box that says: "allow computer to turn off this device to save power"
Now open all devices on the list, and turn OFF all power savers, for every device, as above.
Now Click " OK"
Antivirus: set for "multimedia mode."
This prevents updating from interrupting your media. If you do not have an antivirus with this feature: get a different antivirus.
Set ALL updates to: manual. This prevents an update from eating resources that you would otherwise be using.

Free antivirus from internet: I do not recommend that you install any "free" security tools.
I do not recommend installing "cleaner," "sweeper," "driver helper,"or any free junk from the internet.

Avoid any download which claims to "fix" your computer.

I recommend that you use a professional all-in-one security application - not a free download.

Please consider, when you install multiple security programs, they can conflict with each-other. That's why you should use "all-in-one" pofessional security.
Restart the computer
Open Bios
Turn off Cool and Quiet (if AMD processor) Save and exit bios settings.
Restart Computer
Problems should be fixed now.