IO Meter

We compared the 4 TB Western Digital Black (WD4003FZEX) to the 4 TB Western Digital Re (WD4000FYYZ). For more performance comparisons, please take a look at The Hard Disk Drive Performance Comparison Guide.

Throughput (Random Access)

The small random reads and writes are the most important tests for applications that make a lot of random accesses, so those would be key performance indicators for drives that are used as boot or system drives, but not important for NAS systems.

The 4 TB Red (WD40EFRX) improved quite a bit over the 3 TB Red (WD30EFRX) when it comes to random accesses, particularly in small random reads which the 3 TB Red performed pretty poorly in. That said, this wouldn't make much of a difference in a NAS system, but it makes the 3 TB WD Red a bad drive to use in a desktop or workstation.

Random Access Time

The 4 TB Red (WD40EFRX)'s better random read results were confirmed by its random read access times. As you can see, the 4 TB WD Red's random access times were much shorter than those of the 3 TB Red (WD30EFRX).

CPU Utilization (Random Access)

Throughput (Sequential Access)

This is the most important test for the WD Red because it shows its ability to read and write files sequentially. The large sequential transfer performance is particularly important since many NAS system deal with large files (larger than 512 KB in this context).

Due to the higher variance in its performance, the 4 TB Western Digital Red (WD40EFRX) ended up slightly slower than the 3 TB Western Digital Red (WD30EFRX). The 3 TB Red was particularly fast at small writes, but fortunately for the 4 TB Red, this isn't as important as its performance at large reads and writes.

Sequential Access Time

CPU Utilization (Sequential Access)

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