High speed rules for ground vias

[angelsix]

I know I should keep 20mil distance from other signals on 100ohm diff pairs for example, but what about ground vias?

I've got quite a few places where I could really do with placing a ground via, but its 13mil from a PCIe signal. Do the same rules apply or doesnt it matter those signals being close to a via?

I'm guessing the only thing a ground via would do is act as a void so the void rule would apply, however I cannot find any documents that state the distance to leave between the trace and a void.

[robertferanec]

VIAs are normally fine - you can route close to them. However I do not normally route closer than 0.1mm / 4 mils (Track <-> VIA). Of course, the opening around VIA can not be very large - there still should be ground plane under the tracks.