Greetings romelus; Welcome to the addiction.
Silent running is one good thing but in the shallows your playing with angry destroyers. On the lower left next to your speed dial/control there's a button, press it it changes to a knots reading. In silent running make sure your 3 knots or less, 2 is better. If you can listen-track a dd in early war use your marker and ruler tools. Try to position you aob best you can and less then 1500m. Destroyers can manuver quickly. Trying to use auto lock is like almost usless. Un-lock and aim forward of her bow, fire a steamer as if your aiming to go just ahead of her. Can't tell you how many time this manuver has worked but it takes a bit of trial & error.
Now, your vidio card. Ok it could use more gas but try disabling the event camera.
One thing at a time,
Make sure you have the 1.4 official patch btw.