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What About Performance?
Advanced Format is mainly about expanding the capacity of hard disk drives. However, it does have some effect on performance.
By packing in more data in less space, Advanced Format allows for higher areal density. This results in higher platter-to-buffer throughputs using the same platter and spindle speed. So, we can expect higher sequential transfer rates from Advanced Format drives. The closer spatiality of the data blocks should also improve sequential seek times.
The larger ECC block will not only improve data integrity, it will also allow for faster error checking and correction for the same amount of data. When used with operating systems that have native support for Advanced Format, the larger sector size should reduce the command overhead as fewer commands are needed to transfer the same amount of data. However, we will only see this benefit in future Advanced Format drives that do not use the 512-byte emulation mode.
In addition, data accesses that are less than 4,096 bytes in size will incur some performance penalties. This is because the Advanced Format drive will read the entire 4 KB sector even if you only needed a single byte. The good news is that in this day and age of files that run into tens, if not hundreds of megabytes, such small accesses are uncommon.
Finally, Western Digital ships all their Advanced Format drives with drive buffers that are twice the size of the non-Advanced Format model. The larger buffer will improve the drive's burst performance.
Of course, all this is merely theoretical, based on what we understand about Advanced Format. To find out the exact effect Advanced Format has on the performance of the hard disk drive, we undertook to test two similar hard disk drives. The only difference is one supports Advanced Format, while the other uses the legacy sector size of 512 bytes. Let's take a look at the drives :
The Hard Disk Drives
Model |
Advanced Format Drive |
Standard Drive |
Model |
• WD10EARS |
• WD10EADS |
Formatted Capacity |
• 1,000,204 MB |
• 1,000,204 MB |
Guaranteed Sectors |
• 1,953,525,168 |
• 1,953,525,168 |
Bytes Per Sector |
• 512 bytes |
• 512 bytes |
Platters |
• 4 |
• 4 |
Read/Write Heads |
• 8 |
• 8 |
Spindle Speed |
• Fixed, Between 5400-7200 RPM |
• Fixed, Between 5400-7200 RPM |
Cache Buffer |
• 64 MB SDRAM |
• 32 MB SDRAM |
Internal Data Transfer Rate |
• 111 MB/s |
• 110 MB/s |
Maximum I/O Transfer Rate |
• 3.0 Gbits/s |
• 3.0 Gbits/s |
Average Seek |
• 8.9 ms |
• 8.9 ms |
Drive Ready Time |
• 14.3 seconds |
• 14.3 seconds |
Interface |
• Serial ATA 3 Gb/s |
• Serial ATA 3 Gb/s |
Maximum Height |
• 26.1 mm (1.028 inches) |
• 26.1 mm (1.028 inches) |
Maximum Width |
• 101.6 mm (4.00 inches) |
• 101.6 mm (4.00 inches) |
Maximum Length |
• 147.0 mm (5.787 inches) |
• 147.0 mm (5.787 inches) |
Maximum Weight |
• 600 g (1.32 lbs) |
• 600 g (1.32 lbs) |
Power Consumption |
• 4.86 W (Read / Write) |
• 4.9 W (Read / Write) |
Ambient Temperature |
• 0 °C to 60 °C (Operating) |
• 0 °C to 60 °C (Operating) |
Maximum Shock |
• 65 G @ 2 ms (Read/Write) |
• 65 G @ 2 ms (Read/Write) |
Drive Acoustics |
• 24 dBA average (Idle Mode) |
• 24 dBA average (Idle Mode) |
Non-Recoverable Read Errors |
• 1 error per 1015 bits read |
• 1 error per 1015 bits read |
Load/Unload Cycles |
• 300,000 (minimum) |
• 300,000 (minimum) |
Warranty |
• 3 Years Limited Warranty |
• 3 Years Limited Warranty |
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