Humminbird 788ci – GPS screen not refreshing

I just installed a Humminbird 788ci HD with the external GPS antenna. I’m running version 6.250. I’m using the latest Lakemaster chip. My problem is that when I get the boat up on plane – 15-20MPH or faster, the GPS screen either goes entirely white or I get the bottom half of the chart displayed, with the top half white/blank. It’s not refreshing fast enough.

Has anyone else had this problem? Do I have a bad head or is there a setting I need to be looking at – possibly the vessel speed offset?

Thanks!

Zoom out quite a bit while moving on plane. The lakemaster chips have a lot of data and tend to load slow at higher boat speeds.

I have to zoom out to 200 feet at higher speeds on my 798

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Zoom out quite a bit while moving on plane. The lakemaster chips have a lot of data and tend to load slow at higher boat speeds.

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X2

I have the same problem with my 788ci, but I do not have the external. I always zoom out to 200′ a few minutes before I decide to run to a new spot. I also read that if you have the low water depth highlight(0′-5′) or depth range highlight(10′-14′), it will slow down the map refresh rate. My gut feeling is that processor is just too slow on this unit when using the Lakemaster. My next move was to buy an external gps receiver, guess I won’t be doing that.