Drive Upgrade Considerations

When upgrading to a larger capacity drive, the main thing to consider is whether or not your computer is capable of addressing the extra capacity provided by the larger drive. If the system is several years old this is especially true.

Here are some common thresholds for capacity limitations:

2.1 GigaBytes
8.4 GigaBytes
32 GigaBytes
137 GigaBytes
2 Terabytes

As an example, if you have an 80 GigaByte (GB) drive, and are considering upgrading to a 160 GB drive, it would be wise to verify that your system BIOS (Basic Input/Output System) is capable of addressing capacities above 137GB before purchasing one. If it is, you can safely use drives up to 2 Terabytes in capacity.
To check system BIOS compatibility, contact either the system vendor (HP, Gateway, Dell etc.) or the system mainboard manufacturer. Mainboard manufacturers usually have capacity limitations listed in the specifications on their website.

ATA Controller Cards

A workaround for a capacity issue with a Parallel ATA drive is to install an ATA controller card into a PCI slot in your system.  Drivers will be provided by the card manufacturer to be loaded into Windows or MacOS.  The larger capacity drive would be connected to the card instead of the mainboard so that the card can provide the addressing to the drive and enable larger capacities.  A modern ATA-133 controller card would support up to 2TB in capacity per drive (usually up to 4 drives per controller card).

Serial ATA

For Serial ATA (SATA) drives, all Serial ATA controllers are capable of up to 2TB in capacity so it is safe to assume that when you are upgrading a Serial ATA drive to a large capacity one, it will be compatible with your system.

You can also purchase a SATA-150 or SATA-300 controller to install into a free PCI slot that will enable compatibility with a Serial ATA drive for up to 2TB in capacity (usually up to 2 drives per controller card, commonly up to 4).

External and Networking Products

When upgrading to larger External and Network drive products, the extra capacity is handled by the operating system, so doesn't rely on BIOS addressing.  It is safe to assume that if you are upgrading to a larger capacity External drive product, the same system would be able to handle the extra capacity if your older drive is already supported by the Operating System.

Controller Vendors

Here is a list of ATA and SATA controller vendors.  Seagate does not support or endorse these vendors, but provides it as a convenience for our customers:

Promise Technology



If you have questions about the system requirements in order to upgrade your drive, feel free to contact Seagate Support.

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