It sure would be great it that were true. I find however its not at least on my workstation. My workstation Processors are only 2ghz. Mixer brushes seem to be multi-threaded for I see at least half the process are active when I use a mixer brush like the round fan stiff thin bristles. I see quite a bit activity on 12 processors.. However if I have two layers. My Canon 1D4 16MP image in 16bit color and an empty layer on top. The document is 4886x3264px. If I use a that brush as large mixer brush zoomed out so I'm working on all the image pixels. The lag is painfully slow. If Photoshop Performance setting are set to 4 cache levels and a tile size of 128k or 1028k. If I zoom in to Actual pixels so I'm only working on a screen size number of pixels the lag is still bad if I use a large tip size like 50 to 60px. If I use a small tip like 10px there is some lag but not painfully slow. Lag is bad when working on a large number of pixels and become painfully slow as brush size increases. On my windows workstation...
I think think the only way Photoshop performance could be improved would be to work on the small image being displayed and processing the image actual pixels in the background. Then syncing the the displayed image with the actual image when the background process become idle. Photoshop was not designed to be a Paint program. If your a painter an artiest I would think there are better paint programs in the market place then Photoshop.
at the moment this has really solved my problem and I've been testing it all morning - still no lag, even with larger brush sizes. I'm amazed this actually worked. But I'm still waiting for the consequence.. after all this is Photoshop and you can never have it all with this program. When something seems to have been solved, there's always a catch. But so far so good, I hope this works for other painters as well
What size documents are you testing on? Web size image will not have a problem. What is the highest resolution camera you own. Edit one if your image in 16bit color zoom out so the full image is visible on screen and paint with a large tip mixer brush like the round fan stiff bristle brush.
..thought I'd update a little progress on the issue. I'm not sure if a slow mixer brush is still an issue with the latest versions of Photoshop, but it still lags on my system even with CC14.2.2.
Here's a few points which will cause the mixer brush to lag (on my system, at least):
-'Sample All Layers' is turned on
-The document contains visible adjustment layers (Levels, Curves, Hue/Saturation, etc)
These two points above will always slow down the mixer brush. But I found another solution to get around it, and when I do the following, the mixer brush acts very responsively:
-When the mixer brush lags, try zooming way out of the document, to something like 6.25%. Then, zoom way back in, to 100% and maybe even closer. Now the lag is gone - and the mixer brush is as fast as the normal brush, even with 'Sample All Layers' turned on and all adjustment layers turned on as well. At this point, you can zoom in/out to any level to keep editing/mixing if you need to, and the brush will still be responsive.
What slows it down again is turning on/off any of those adjustment layers, or switching to another layer and doing some editing. When returng back to the layer that you're mixing on, it slows right down again. But then zoom way out, then way in, and the lag disappears. At least on my system - I don't know if this is specific to my setup, or why it's happening, but I hope this will also work for others experiencing the same problem.
-Last, instead of zooming out to 6.25% and then back in, you can try going to "View Print Size" instead, and this also speeds up the brush.
When the mixer brush lags, I zoom way out of the document (to 6.25% or whatever- but make sure you zoom out using "zoom with scrollwheel" - so use the scrollwheel to zoom). Then, click once on the empty canvas area surrounding the document (the empty grey space) and then zoom way back in again - and the lag is gone.
I don't know why, but this works on my system. I hope it works for other users as well.