Memory cards and GPS writing speed

[VinnyR11]

I recently purchased a Garmin 60Csx for hiking and the bike which I am lovin'.

 

At times, when I'm zoomed out pretty far, the map drawing speeds are slow. Is this a function of the GPS? Would upgrading from a Class 4 to Class 6 memory card help at all?

 

I understand that setting the map at more detail requires more draw time. I'd like to know what function the memory plays in this.