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Partial fix Serious performance problem in Reply field on Opera (10-12x) Presto engine

Just started to test new XenForo engine on all browsers and found serious performance problem in forum's Reply field on Opera (10-12) Presto engine. I know, this browser's support was suspended even by developers but still it's one of the best browsers ever and last version was in 2014.04. So it's just year ago and still can be fixed.
Still it can be downloaded from:

Video for example:

I typed messages in one forum board that just installed XenForo engine. And see how it's really slow typing in Reply form on Opera. Every letter is slowed down nearly a second (up to 0.5 sec).. So it's hellishly hard to write down. But the performance is normal when push down any key (to make it repeat frequently). So the problem somewhere in letter processing... Then I even disabled javascripts - but it didnt helped. A big CPU consuming on typing every letter. And found something more about this bug: The more posts page contents - the more it slows down and much cpu time consumes. Still BB code editor (simpled) works smooth and no unnormal CPU usage.
The problem is only in Reply form, and nowhere else to be found..

Tried on Opera 9 (2007) but the answer form didnt appeared there at all:
Pushing answer button goes to error:
Extended mode (none field visible)

Chris D

XenForo developer
Staff member
I am currently typing this using the build of Opera you make reference to above.

It is working absolutely fine, to me. I have tested it on my own site, here, and a local development site and I cannot reproduce the issue.

In my own personal opinion, I wouldn't call this "one of the best browsers". Although typing into the editor is as fast and responsive as it is on any other browser, the general experience of browsing with this browser is very noticeably slower for me. Things that happen in a fraction of a second in Chrome seem to be taking over a second or more in Opera.

Putting that to one side, though, this bug can't currently be reproduced as shown in the video.
It is working absolutely fine, to me. I have tested it on my own site, here, and a local development site and I cannot reproduce the issue.
Ok. Understood. The problem i have is in CPU time it uses. I have 2000mhz single core cpu and it's used totally . Seems you are using multi-core CPU and much more mhz so it's not noticable because it consumes nearly 2500-3000mhz when typed. Just look at your cores loading when typed in this browser, and compare to other browsers.


XenForo developer
Staff member
We haven't made any changes to target Opera 12 specifically -- and it's unlikely that we would given that it has been superseded by newer versions and a newer engine.

However, we have done some performance analysis on the RTE and identified a couple areas we could optimize and that does seem to reduce the slowdown in Opera. If you still have problems though, I would have to recommend disabling the RTE or upgrading to a version of Opera based on Blink.