Ok many thanks; I see a few of these things here that could definitely help. To you; and the other responder; in general this was just a test script to do something on the canvas to get the issue to happen. So for the real thing, i'm generally processing some kind of data input to figure out what the pixels are. (say a video input, some telemetry data, etc) So that side of the problem doesn't bother me; nor does the overall speed of the render. I am running on a beast of a work machine (precision 7820 tower); but it does not have much in the way of graphics support. So that could definitely be part of the problem; but I have seen this issue before on my home machine with at an least decent graphics card. I have also done stuff drawing tons of lines and good results with a canvas; but probably not nearly as many as 400x400 items going to the canvas at once. I am running in windows and my company also has a ton of spyware / antivirus stuff that kills all productivity, which could be at play. I will also try the other responders single call to the canvas (if that's possible in my case); I need to study what he was suggesting more. (I am not really interested in drawing a checker board; I'd generally be drawing something real) But I assume there's probably a way to stack up all my pixels into a single call and only have 1 tag/object in the same kind of way he did. BTW: i am running strawberry perl on windows: This is perl 5, version 30, subversion 0 (v5.30.0) built for MSWin32-x64-multi-thread Thanks; I will try to get back to post my results in next day or so.