Check that you have the same priorities enabled as those will interrupt scan and do its thing and after that will let the scan continue. If scan time where the same it could be the SD card interface that works differently and that can be checked when the scanner works as a mass storage device, when you program or read it, and see if the write and read times are the same.
Product manufactures always tries to reduce costs and after a while they check the design if they can remove components or replace them with cheaper alternatives to reduce production cost. BCD436 had several changes done over time with 3 or 4 different circuit board designs and had components removed including one important filter capacitor for a data signal that then created interference in the 400MHz band that wasn't noticed when tested with a signal generator or an external antenna some distance away from its CPU circuits.
It could be a cost reduction design change to the SDS200 that have made it slower, so it have to be verified with newer SDS200's. The first 3 digits in the serial number are the model number and then comes the manufacturing plant and following that are the manufacturing date and the last 6 digits are the serial number for that production batch.
There's lots of internal spurious signals in SDS scanners that the scanning process will hesitate at. The lower in frequency the more hesitation and slower scan speed you will get. It's less problems in the 700-900MHz range and if you set the squelch to max it will not detect much of the interferences. Set a 20MHz search range in the 800Mhz band and compare both scanners. Search are done at full speed, some 80ch/s, and to get the scan speed, that will be half of that, you will have to create a scan list with a lot of frequencies. In ARC536 it's easy to create those lists and I guess ProScan can do the same.
/Ubbe
