For domestic market (China) there are two versions of hardware: one up to 1 GHz and 2 GHz. 2 GHz version has 4 ADC and has 5GS/s at all times (10 GS/s with ESR). Also, if you look closely, it has slightly different memory architecture (Unified memory : 500, 250, 125 MS as opposed to to 2x 250/125MS) and therefore different FPGA configuration and such. Also, a 2GHz capable front end.
The architecture for 2GHz domestic one was probably used as basis to develop 8 bit version of that, and with 4 (different type) 8 bit ADC was made in worldwide platform, that is single for all bandwidths (500MHz, 1 GHz and 2 GHZ). They all share same motherboard, front end etc. There are software upgrade options that use that fact, otherwise it wouldn't be possible.. As mentioned by Nico many times, BOM optimization, streamlining development and such.
Therefore domestic Chinese SDS6000 series is same family, but worldwide motherboard is different board and should be viewed as such.
@Tom, difference in power ( <= 1GHz and 2 GHz domestic China version ) comes from, as explained, different hardware..
Variation in consumption comes from scope CPU load, and channels enabled..
With all math channels, decodes, digital scope power goes up. In stop mode it goes down..