Overall, the comparison yields a dead-heat with razor-thin margins. The 1 meg 5120 slides past the 512k version by a negligible 1% in the Business Disk WinMark under Windows 95. The High-End Disk WinMark displays a 0% difference. Under NT, the Business Disk WinMark shows no difference between the two drives, while the High-End tests yield a surprising but still negligible result: The 1 meg drive actually lags behind the 512k version by 3%.
A closer look at component High-End WinMark scores is warranted. Here, three results leap out with margins higher than the rest. Under Windows 95, the 1 meg Maxtor outperforms the 512k drive by 10% on the MicroStation SE test. The situation reverses itself when it comes to Adobe Premiere tests- here the 512k version pulls ahead by 10%. It seems these two results balance each other out, netting identical performance in the average score. In Windows NT, however, the 1 meg drive's advantage in MicroStation is erased, yet the 512k drive manages to stay ahead of the 1 meg disk by 9% in Premiere. Thus, the drive with the smaller cache actually pulls ahead slightly in the overall score.
ThreadMark presents virtually identical performance for the two drives. In both Windows 95 and Windows NT, the 1 meg 5120 edges by its 512k brother by margins of less than 1%.
What should we conclude from these differences? First and foremost, these results show that your opinion of the DiamondMax Plus 5120 should not change one bit. If you thought it was a great drive, the 1 meg unit is still a great drive. If, however, you feel the 5120 falls short in areas that count, the extra cache doesn't help one iota.
Looking at the bigger picture, however, the results displayed here show us something that shocks "common wisdom": A larger buffer in and of itself is no asset and makes little difference in performance. One of our more prolific participants in the StorageReview.com Discussion Forum hypothesized such a theory a while back. Rather, it's the ineffable, undisclosed "firmware/drive electronics" that make more of a difference.
Take a look at the likely scenario here: buffer size is doubled with little change in firmware. Net result? Little change in speed. Take a look at the converse: the DiamondMax Plus 5120 and Fireball Plus KA, though possessing only 512k of buffer, nevertheless manage to significantly outperform the 2-meg-buffer IBM 22GXP/WD Expert in several tests. What can we ascribe the excelling results to other than superior firmware/programming?
An increased buffer size and corresponding changes/improvements in algorithms/firmware may very well yield improvements one would expect. Indeed, improvements in algorithms/firmware alone can propel a drive to the forefront (again, observe the Atlas 10k vs the Fujitsu MAG3182LP). As shown here, however, increasing buffer size alone is virtually meaningless. It's quite a pity, as buffer size is quantifiable and thus "spec sheet-able" while superior routines are more abstract and not an easy target on which a manufacturer may focus marketing muscle.