I've a vu+ solo2 and a swiss TV card and quite a lot of plugins. Nevertheless I have no issue with switching speed. The only non standard I have is a 8GB USB mounted as HDD and so outsourced MP3Browser cache, the E2iplayer download / temp and the setting backup directed to the USB. Can you read out the memory information (Menue > Information > Memory).

If you are short on memory I would suggest deleting all but one setting backup and all languages not required. And you can uninstall the not required skin versions in the plugin section.
Good luck