I recently upgraded to Thunderbird 5. First impressions: pretty, and pretty slow. Lots of lag when deleting email made for a real pain when removing the 100 or spams and viruses that show up in my inbox every day. There’s a fix. It also doesn’t play nice with ESET security. No fix available.
The lag when deleting each bogus email in the inbox was intolerable. It’s likely the delay wasn’t so much in the deletion, but in displaying the next email in the list. Like the FireFox font issues, this also relates to hardware acceleration.
Per this thread Why is Thunderbird 5.0 so SLOW? CAUSED by direct2d toggling gfx.direct2d.disabled and layers.acceleration.disabled to true (Go into Tools → Options → Advanced → General and click Config Editor) speeds things up. It did for me.
More troublesome was finding out that ESET is not compatible with Thunderbird 5 – or 4. I’ve tried ESET a couple of times, but always gone back to Avast + Sphinx because ESET seems to make the S3 sleep issues worse on my desktop. I decided to give it another try and went through the thrash of uninstalling the other stuff, fixing up my POP3 and SMTP settings, and installing ESET. None of the ESET features showed up in T-bird.
ESET has said on various security forums that ESET 5 (the next version) will support T-bird 5. Of course, by then we will be at T-bird 6. Or 7. Or 8. Thunderbird 5. Is ESET Smart Security compatible with Thunderbird?
I’ve decided to continue with the ESET experiment, so for now I’ve reverted Thunderbird to 3.1.11.