speeding up opencpn

[ddelorme]

i have noticed for a while that my opencpn was laggy when scrolling or zooming/ unzooming.
my system is a rpi5 with 8gb of memory, MacArthur hat and pci base for ssd drive.
well after a little digging i realized opencpn was being very conservative with my map cache and memory. 
i changed the follow in opencpn.config
 [settings]
GPUMemorySize=2048
MEMCacheLimit=4096
NCacheLimit=200
i don't know if the GPU setting is necessary but i added it anyway..
the change was rather dramatic and has fixed the issue.

[ddelorme]

after thinking about this i suspect the biggest boost was

GPUMemorySize=2048 not really necessary as rpi5 allocates video memory from system memory
MEMCacheLimit=4096 default half of memory
NCacheLimit=200 default 20

i should test this without the first 2 values. please feel free to test this and post what you find..