Dataflow Gen2 refresh extremly slow (compared to Gen1)

Hi JayJay11 

Thanks for usng Microsoft Fabric Community.

Apologies for the inconvenience.

Here are some possible reasons and solutions for your problem:

Dataflow Gen2 has some limitations. For example, it does not support Data Factory Fast Copy, duration and binary columns, or spaces or special characters in column or table names. These limitations may affect the speed and efficiency of your dataflows.

Please refer to the documentation for more details.

Dataflow Gen2 may require some optimization. You can use the refresh statistics to analyze and improve the performance of your dataflows. For example, you can check the source and destination throughput, the partitioning strategy, the staging option, and the query folding level.

Please refer to the documentation for additional information.

No, Microsoft Fabric Free Trial Capacity is not a sort of shared capacity. It is a dedicated capacity that you can use for 60 days to test out the Fabric experiences with 64 capacity units (CUs) of throughput.

For more details about Microsoft Fabric Free Trail please refer this document.

If the issue still persists please do let us know. Glad to help.

I hope this information helps. 

Thanks.