The Definitive Chunksize Optimization Guide

Winstone 99 1.1

Chunksize	8	16	32	64	128	256	512	1024	2048	4096	8192
Business Winstone 99	20.80	20.57	20.63	20.70	20.77	20.67	20.73	20.70	20.73	20.73	20.87

Don't be fooled by the chart. The difference between the lowest and the highest score is only a mere 0.3 Winstone points. That's less than 1.5%! So, you can say that the performance difference, in Winstone 99, between the different chunksizes is negligible. Note that the default chunksize (512 byte) performed slightly better than average.

Business Disk WinBench 99 1.1

Chunksize	8	16	32	64	128	256	512	1024	2048	4096	8192
Business Disk WinMarks	2820	2823	2823	2816	2813	2803	2820	2823	2817	2827	2820

In the Business Disk portion of WinBench 99, the difference between the highest and lowest scores was only 24KB/s, which amounts to a meagre 0.86% difference. Again, negligible differences. The chunksize of 256 bytes scored the lowest while the 4096 bytes chunksize scored the highest.

The default chunksize of 512 bytes performs slightly above average again.

High-End Disk WinBench 99 1.1

Chunksize	8	16	32	64	128	256	512	1024	2048	4096	8192
High-End Disk WinBench 99	9223	9230	9093	9213	9360	9057	9383	9103	9257	9260	9133

Here, you'll notice that the 256 byte chunksize scored the lowest again. The performance difference between it and the highest scoring chunksize (512 byte) is 326KB/s. That's a 3.6% difference so it's noticeable. Now, let's take a closer look at the effect of chunksize on various applications in WinBench 99.