I am having issues with Krita 3.01 on openSUSE 42.1 Plasma. The problem is that with painting in that the brush seriously lags behind the curser when I'm painting. My current cpu is AMD FX8350 with Nvidia GT 640 graphics card and driver 375.26.

I have read that AMD cpu's are not so compatible as intel, but I really cannot afford to do a replacement.... At least not for the near future and I have no other issues with speed with anything else... so this would seem overkill. My graphics card is a little old in the tooth now and I was wondering if this was the issue. Now it seems that Nvidia are often recommended on here but openSUSE only offers proper support for AMD cards.... I'm confused.... at least for the free drivers. If this is an upgrade that would make a difference then what should I look at? Memory bandwidth, GDDR5, Speed, Top game spec or pro? (I don't play games but I am thinking of blender in the near future).

Or would I be better just buying an ssd drive?????

Sorry a lot of questions but it kind of boils down to the lag!!

The AMD FX8350 is quite a powerful processor, much more than you need to run Krita. (It's twice as powerful as my old dual Xeon CPUs running on an old motherboard with DDR2 memory and PCIe2 backplane and I don't have brush lag.)

There is no reason why the AMD cpu shouldn't be compatible. They are made as a copy of the Intel cpu and some even have improvements over Intel.

The Nvidia GT640 is more than good enough for 2D work such as is done in Krita. I used to have an old Nvidia Quadro FX1700 and that showed no lag when using Blender and moving the view around quickly. Similarly it had no problem with GIMP working on large pictures with many layers. I now have an Nvidia GTX 750 Ti which is overkill for 2D work.

The video driver in OpenSUSE may well be worth investigating. Nvidia might have a suitable driver on their website. I suggest that you install GIMP and see if GIMP has similar lag problems. If it does then you have some kind of computer/video problem. If not then you have some kind of Krita configuration problem.

Have you tried enabling/disabling Open GL in the Krita settings? There are various other settings that you can change to test if they improve matters.
Do you have the problem with all brushes or just big and complicated ones? Do you have lag with just a simple, small, one layer image?

An ssd drive is good for many reasons but it won't improve performance except for boot time, load times or if you run an application that does lots of repeated disk access as part of its activity.

Good luck

P.S.How much RAM do you have and how much is in use when using Krita?

GIMP doesn't use OpenGL -- so that's hardly relevant.

Trying GIMP wouldn't be relevant for tracking down OpenGL problems. However, cursor/brush lag in GIMP would indicate a problem outside of Krita and it's an easy test to do.

I forgot to ask what the input device is. Does it lag with a mouse? Is a pen tablet being used? If so then what type? Is the latest Linux kernel being used? Have the tablet supplier's or any other Linux drivers been installed at all? (With Linux Mint Serena 64-bit, the kernel/Mint drivers work fine for my Wacom Intuos Pen & Touch tablet but I don't know about OpenSUSE.)

Okay thanks Ahabgreybeard. I am using a Wacom intuous 3 tablet for input.

So from my understanding of what you are saying, I should look at openGL and possibly the graphics driver as culprits. Or maybe it's the way Krita is set up under openSUSE. One of the main reasons I am using Suse is that KDE is very well supported so that would surprise me although, obviously I'm not disagreeing as I have had more success with Kubuntu (I just don't like the *buntu family as such). I will look at openGL now and report back. Can I ask if this would have any serious impact on the desktop performance as a whole though?

The kernel is 4.4.36-8-default LTS if that is helpful.

I just read read your reply and I realise now that the openGL setting is in Krita itself and yes that does seem to have cured the lag!! Very happy again. Out of interest though has there been a change / regression of openGL support since the 2.9... release or is this peculiar to SUSE? Should I raise a bug with the krita team?

Many thanks for your responses

The thing about disabling OpenGL in the Krita settings is a well known fix for brush lag and is not something I understand. The Krita team are well aware of it.

As soon as I saw the specifications of your computer I knew that it was more than capable of running Krita properly but I just wanted to make sure there was nothing strange that may have been making it perform badly, hence the suggested test with GIMP and the other questions. (As a matter of interest, my Wacom Intuos Pen and Touch didn't have proper touch behaviour until a recent kernel update/backport. There are many little things that can affect your experience.)

Yes I have to agree with you there. In fact that that's one of the reasons I choose suse as they are particularly hot on support in the forums. One thing that got me wondering, was their recommendation, with the latest release of opensuse under plasma5 , to use AMD gpu's as the free nvidia driver is broken..... for them anyway. I don't know why but it coincided with krita breaking....

Still all seems well now and thank you so much for your in depth answers