During the conversion, were the L-M vi's converted to LV7 or fully replaced? There appear to be a few changes between 6.1 & 7 LM vis... several of the lower level subvi's go changed to CIN's, vs pure LV. You may want to see if it's just LV 7 running slower (LV 7 uses more resources than 6 in general... I've got both on an old 400 MHz AMD w/ 96 Mb of RAM... 6.1 cruises... 7 is a drag).
You might want to try using the LM vi's from 6.1 (do a save out w/ options to save all vi's), to see if it's LV7 itself or just the newer LM vis that's slogging it down.
