I play online and multiple tables. 600 hands takes ~90 minutes at 6ish tables. Each table is ~75hands/h. I can play up to 12 at the same time, but my play suff

I play online and multiple tables. 600 hands takes ~90 minutes at 6ish tables. Each table is ~75hands/h. I can play up to 12 at the same time, but my play suffers and I don't feel like I'm able to focus and get better.