Your thread has been moved to the more appropriate hardware forum.
Only having one stick of RAM will cause a severe bottleneck.
What is the brand and model name or number of the PSU.
Download then run
Speccy (free) and post the resultant url for us, details
here, this will provide us with information about your computer hardware + any software that you have installed that may explain the present issue/s.
To publish a Speccy profile to the Web:
In Speccy, click
File, and then click
Publish Snapshot.
In the
Publish Snapshot dialog box, click Yes to enable Speccy to proceed.
Speccy publishes the profile and displays a second
Publish Snapshot. You can open the URL in your default browser, copy it to the clipboard, or close the dialog box.