We've had a few reports of slower than typical import speeds specifically with the voter file importer. Signups per second are being imported 3x slower than similar imports done in the recent past.
This has been observed through importer tool (People > More > Imports > Voter file import) as well as the API importer
If you are experiencing similar issues with any of the importer tools, please follow this card and email email@example.com.
Thanks Thomas - we are monitoring this and it seems like import speeds are back to expected - we'll keep this open for any new reports.