photoshop rectangle tool and drag image lagging

Please read this (in particular the section titled "Supply pertinent information for quicker answers"):

https://community.adobe.com/t5/Community-Help/Guidelines-Tips-for-the-Adobe-Forums/td-p/4788157

What are the Peformance-relevant settings? 

What are the image’s pixel dimensions and bit depth? 

https://helpx.adobe.com/photoshop/kb/optimize-photoshop-cc-performance.html

Hi

What exact version of Photoshop and operating system do you have, have you tried resetting the Tools

If that doesn't help try a preferences reset