I think everyone's jumped to conclusions on this. The profiles actually show that GC is not the cause. The profiles show a long frame, and only a tiny amount of time taken up by GC. For example the profile posted by TheRealDannyyy shows a frame taking 68ms, but GC only taking 8ms of that. Why didn't it schedule another frame in the remaining 60 ms? It looks like it could have done, because it wasn't busy doing GC, but it didn't. Right now we don't know why, but it is too early to blame GC, especially since it looks like GC finished quickly with plenty of time to spare. ...
Ashley Why would GC do any work at all? I'm for incremental GC if necessary but in Chrome 69 those GC calls seem to be all over the place, regardless of available system memory, it's almost like GC is always under pressure to release memory.
I couldn't find a more reliable example besides the one I posted before, could reproduce this on Win7; 8gb RAM; GTX 1050ti (4gb); Quad Core Cpu 3,6ghz. Taking a quick look at the open bugs for M69, looks like it's quite broken with several performance related problems.
Again, I think best thing would be to wait and see if a hotfix will solve all the issues including this one.