you know what may also help? go to your start butten and go to "my compluter" and right click it and go to properties>Advanced, under performance click the settings button, then click "adjust for best performance" may help if you havnt done this yet, it helped me lots. ^^'
Hello Vasyl. I have been experiencing some Photoshop Lag. Have you tried removing it from using the Video card? Sometimes it kept me from drawing because of it. To disable it go to photoshop > Edit > Preferences > Performance > Untick (Use Graphics Processor. It helped me quite alot so check it out