Is it normal for the R4 to run slower when upgrading SDHC

I just upgraded my 4GB to an 8GB sdhc, but now the menus are a little slow when loading
is that normal?got like 77 games on there and it's and R4 ds lite
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the games runs fine, but loading menus are slow

is it a normal r4 card if so the biggets card they can run is 2gb card