I find I can avoid this lag if I'm more precise with the brushes and resist the urge to just smear around the canvas (which is fun but not productive) so it's mostly a minor annoyance for my rig. Ive completely switched to using ArtRage 5.
(Easier to upgrade RAM than processors) There's also Paint Tool SAI which functions differently but has custom brushes everywhere on the internet and is tablet-intensive, but is also more expensive and not on Steam, so not likely to go down in price. importing and exporting custom brush settings and a range of surprisingly. differently but has custom brushes everywhere on the internet and is tablet-intensive. This video is a quick tutorial for fixing the lag in the custom brushes of Artrage 6.To fix do the following:1. In this article you will find carefully gathered list of 15 free ArtRage brushes and stickers that you’ll definitely find useful if you’re coming on board. One of them is ArtRage, a digital painting and drawing application by Ambient.
If you're really serious about that quality, you might want to consider upgrading your RAM if possible. But when it comes to SFM i lag out and crash upon map load. However, they aren't as focused around the quality and realism as ArtRage. Sorry if I'm taking away customers, but Artweaver and FireAlpaca are both tablet-intensive painting programs that are free and use less resources. Thats not how programs like Clip Studio and Photoshop operate.
I'd like to point out that I have 4 gigs of RAM and still lag with ArtRage 2 and ArtRage Pro demo if I make too many strokes with a brush at the same time, it takes a while to calibrate and is especially slow with the palette knife. I think this was version 2 or 3, while currently available one is version 5.