I doubt anybody's done extensive testing or benchmarking for performance benefits when you enable/disable that feature. Most people probably leave it to the default (unchecked).
But heres some history. That setting exists to actually fix a bug in Win 3.1 that led to many legacy apps relying heavily on flush calls (forcing hdd to write buffered data to the disk). The reason they did this was because flush calls were extremely fast and the reason they were so fast was they didnt actually work! The feature was broken, lol. So when MS fixed the issue in Win 95, all such apps slowed down to a crawl. To fix this MS added back the option to break the flush calls.
Read here:
Windows Confidential: The Power of Bugs