Dual SIM - can both be 3G ?

[wgrs]

I use Dual SIM with one Sim for voice, one for data. Works well, but the data Sim uses 3G while the voice Sim uses GSM.

Can the voice SIM also be on 3G? Some providers don't support GSM any more, in that case I would be on data only?

 

[gpobernardo]

From post#14 in this thread, I partially quote,

On a Dual SIM 3G phone only one slot at a time can use 3G. You can toggle between the slots and the SIM trays momentarily reset (not the whole phone).

 

[Tankid]

Is there any way to force both sims to use 3g at the same time? It is really annoying to use Lumia 730 in Korea since there is no 2G network there