How to make best use of a Intel Arc B70?

I have a RTX 5090 in my desktop PC for local coding assistance and gaming and I have been loving it with Qwen3.8 27B Q4\_K\_XL.

I managed to get a B70 on the cheap and its great, but using it in split mode with the 5090 to ensure I get full context halfs my T/s (which is expected due to the memory bandwidth).

Would I be better off running the B70 with a smaller model to offload tasks to? Or just accepting the slower throughput and keeping the larger context?

I'd especially like to hear for anyone who has a similar mismatched GPUs setup.