How is your GPS Receiver connected to your 997 unit slimeyslab?
To get the faster update rate it must be connected directly to the unit either at the GPS connector or on an AS-YC y-cable.

Just to be clear on this: by the end of last the 2009 calendar year we had released software for the units that allowed for a faster GPS update rate (but only if the GPS is directly connected to the unit). This did not change how the unit determines whether it is moving or the direction that it is moving – it only allowed this information to be charted more often. I believe that these are only issues when moving very slowly and has nothing to do with how fast the unit updates its charts. The original complaint was for a slow response to direction change which has been taken care of. Determining movement and direction of travel at very slow speeds is something that is still being looked into.