The WD6402AAEX has a price premium compared to its sibling WD6401AALS. And we previously reviewed the WD6401AALS and found the results to be a little disappointing. Although the real world performance should not be impacted much, it is still a bit dismal. You would expect a bit more from the dual processor technology that Western Digital introduced starting with the WD6401AALS. Benchmarks and reviews are influential in consumers buying decisions.
So here we are with the WD6402AAEX. Let's see if the trend is broken by this drive. It has the same spec as the WD6401AALS only that it has double the cache at 64MB and has the third generation SATA 6GB/s technology.
It seems Western Digital did it right with the WD6402AAEX. From synthetic benchmark of HD Tune above, it is bounds and leaps faster than the WD6401AALS. Seems the cache plays a big impact on the drive. Doubling the cache has a very profound effect on performance.
Thanks to its new generation controller, the burst speed of the drive broke the SATA 3GB/s speed (theoretically 150MB/s). HD tune measured burst speed at 153MB/s transfer speed.
On average, the WD6402AAEX is faster by more than 20MB/s than the WD6401AALS. Now that's performance!
The WD6402AAEX impressed us a lot that we bought another drive and made a RAID0 (stripe). Here's how that 2-disk WD6402AAEX stripe performed.
It seems the 640GB Caviar Black is cache hungry. Not much difference on the areal density between these drives, so it must be the cache. And as it seems, the cache hit it big time. I wonder then if mainstream desktop drives will ever be given a generous 128MB of cache.
Acknowledgments, again, to my good friend Xavier Zulueta of OCXPH for testing the WD6402AAEX for me.
