uses 3 instead of 6 GB video card

About 4 months ago I downloaded Total war shogun 2 and the settings showed 6 GB and now 3 GB








I downloaded avast premium, did a scan, read many articles on how to determine the miner. And it seems to me that all of them are outdated miners have already learned how to bypass task managers, because when I turned on the task manager, the mining process abruptly stopped and either my imagination plays out, but when I turn on the dispatcher I can see how all processes are loaded in the region of 70-99 percent.
Or maybe the problem is something else, I hope you can help)