We have been suffering, maybe forever, with painfully slow Magento admin performance. It could take 30 seconds just to login for an admin user (users with less privledges did not have issues). The issue seems to be related to a module called VladamirPopv and webforms.
The strace revealed many queries like the following repeating over and over:
SELECT `webforms_results_values`.* FROM `webforms_results_values` WHERE (webforms_results_values.result_id = 22381)"
There were 34127 queries referencing "SELECT `webforms_results_values`."