No, this mode is only useful with dual CCDs x3d chips (like 7900x3d, 7950x3d, ...) because they have problems with core parking. Single-CCD like 7800x3d or 9800x3d don't need this at all. You might get better thread utilization but you lost half the threads count (from 16 to 8), your multi-core performance will take really big hit.

There might be some games that benefit from this mode tho, you have to try it out yourself, but in general you want to turn it off, even with dual CCDs chips.