Q: Has anyone else noticed that apple mail is slower in El Capitan than Yosemite

No. I have noticed no difference whatsoever.

Pete

Mail.app in El Capitan is very slow for me, especially when either switching between views/mailboxes inside the app, removing spotlight searches (it can sometimes take 15 seconds to go back to an un-searched list of messages) and switching into Mail from other apps. I've no idea why yet.... any ideas?

I am often getting very slow mail operations.  Sometimes it is slow when I open a message, taking 20 seconds to display the content even when it is text only.  Sometimes I check my mail and it takes forever to check. Showing it is "Copying Messages", "Checking for Mail", "Downloading messages" and it just stalls. This is running on a 2.6Ghz i7 with 16GB 1600MHz DDR3 and brand new "APPLE SSD SM768E" drive and System 10.11.1 OS.

Apple Mail is considerably slower for me as well. Archiving messages sometimes takes well over 10minutes for the message to visibly leave my inboxes. Quite frustrating. Attempts to repair permissions and clean the Mail volume index don't produce results. Quite frustrating.

MacBook Pro (15-inch, Mid 2012)

Processor 2.7 GHz Intel Core i7

Memory 16 GB 1333 MHz DDR3

I did a clean install of El Captain. I have basic software - Adobe CS6 - but other than that very little extras, additions or plug-ins. One of the things that I am having trouble with is Mac mail. It is very, very slow. Loading of content is very slow. I am really hoping that an update will fix this.

mid 2011 mac mini with 2.7GHz Intel Core i7/ 8 GB 1333 MHz DDR3/ AMD Radeon HD 6630M 256 MB

I've been trying various things (reindexing mailbox etc etc) since I installed El Capitan. Turning off iCloud Drive for Mail seemed to help, but then Mail slowed right down again. What does seem to help is keeping the number of mails in the inbox(es) right down - I usually have 20K+ mails hanging around from various mailboxes (I just archive them every few months). I just did an archive run for all mails more than a month old, am back below 5K mails in the inbox and mail is much faster. In previous versions of OS X/Mail this was never an issue.

Latest progress on this for me is the following:

• Rebuilt mailbox and deleted logs (see various answers) - didn't see much improvement.
• Turned off Apple Mail's connection to iCloud Drive - thought it helped for a while, but things slowed down again quickly.
• Clearing out old mails from Inbox - looked like it was helping for a couple of days but turned out not to be the solution.
• Disabled an old POP mail account which wasn't working (following this discussion about old Exchange accounts - https://discussions.apple.com/thread/7252807) - so far Mail seems to be a lot faster. Will come back after a few days and update on whether it's still looking good.

Following up on this one, reducing the amount of mail in the mailbox didn't end up helping for more than a couple of days...

After upgrading from Yosemite to El Capitan, I had also performance issues with Mail (and other things). The issue with Mail was largely resolved, after I completely rebuild the Spotlight index on the boot volume. Before this, Spotlight searches were slow to a crawl, after this, Spotlight searches were snappy again, namely in Mail.

The Terminal command for rebuilding the Spotlight index is:

sudo mdutil -E /

Re-indexing will take hours. So it might be a good idea to start the command at night, and leave your Mac indexing overnight.

Even after the latest El Capitan update (10.11.2) and trying all sorts of other stuff, Mail is very very slow to move views, open mails in new windows etc etc. Using Activity Manager I've now noticed that accountsd hits 100% CPU whenever this happens. Anyone know what this does?