There is a magnetic top vent filter that comes with the case but it covers the top rear exhaust fan so I don’t really want to put it on.
Yes, I know the pc is dirty, but I’m getting a new PSU after Christmas so I’ll clean it then.
i personally leave the dust cover on the top unless I’m playing something that will heat the pc up a bit more than normal, then I take it off to help with cooling. I have birds, so their dust and feathers seem to migrate to my pc, so normally I just leave it on at all times.
Safe to put on, and I would. It will prevent dust from collecting via gravity, and it will keep dust from getting sucked in during normal use.
It may not look like it, but even if your main intake is at the front blowing horizontally, some air is inevitably being pulled in from the top by your CPU cooler and the exhaust fans.
It won’t hamper exhaust capabilities to any significant degree.
dust from collecting via gravity
that is why I was thinking out covering it, but I don’t want to cover the top exhaust fan on the rear though.
The filter was specifically designed and manufactured by the people that made your case to put it in front of a fan. You’re not hurting or damaging anything by using the product as intended.
Unless it’s particularly restrictive, like made of a tightly woven fabric, it shouldn’t be an issue for heat.
I have a mesh filter on my own case on top (NR200), and I’ve never had a problem with thermals. I also use a vertical exhaust pattern instead of horizontal, so if it was a problem, I should have seen it by now.
My cat usually covers it for me when I’m gaming.
Those filters are best used when in front of an intake. For exhaust it is just adding an unnecessary restriction. It is fine to leave it off.