HDD - which is better UDMA or IDE?

  bliksem 15:04 05 Feb 2003

Hi All, Im looking to buy a bigger HDD (80 gigs) and would like to know whats the best in my price range ie £100. Am I right in saying I want a 7200rpm as its faster than 5400rpm and is there a difference between UDMA and IDE. Help ?!



  MartinT-B 15:13 05 Feb 2003

The faster the disk spins, the lower the 'seek time'. 7200 is better than 5400.


ultra direct memory access

UDMA defines a new protocol for the interface between the hard drive and the computer. It improves upon the ATAPI/EIDE standard by doubling data transfer rates to 33MB/sec, which translates into faster disk reads and writes. For users to take advantage of UDMA, both their system and hard drive must support the protocol. UDMA retains backwards compatibility for previously existing hardware.


integrated device (or drive) electronics

This hard-drive interface has all of its controller electronics integrated into the drive itself. The IDE specification handles hard disks up to 504MB in size. Because of its simple instruction set and the short route between controller and drive, it's a quick and easy type of drive to use (unlike SCSI drives and the older Enhanced Small Device Interface (ESDI) drives from the late 1980s). But because it's a limited specification, IDE is gradually being superseded by an enhanced version, EIDE.


enhanced integrated device (or drive) electronics

A second take on the PC platform's IDE drive interface that increases the previous maximum disk size from 504MB to more than 8GB, speeds up the data transfer rate to more than twice what IDE was capable of, and doubles the number of drives a PC can contain, bringing the number up to four. On the PC platform, EIDE gives SCSI-2 a run for its money, and while most people agree that SCSI-2 is technically superior, EIDE is cheaper to implement, which gained it widespread acceptance.


Small Computer System Interface

While the PC was settling for rankly inferior alternatives, the Mac adopted SCSI as its expansion standard. With SCSI, you can add up to seven new devices to your computer and depend on them to deal with single-interface issues by themselves. It's a robust standard, and it's rendered even more so with its latest implementation, SCSI-2. But it requires some system overhead, slows down your computer's start-up, and demands that during installation you handle device ID administration and a process called termination that closes the SCSI circuit. Pronounced "scuzzy" by those in the know.

And then there's Serial ATA or SATA

  bliksem 15:20 05 Feb 2003

But you've blinded me with science. I do know I don't want SCSI. Basically will a UDMA 80g HDD 7200rpm work fine with my Athlon XP 1600+. ie the motherboard should be able to handle this?



  SpyMan²°°­­³ 15:21 05 Feb 2003

Was that a Copy and Paste Martin??

  rickf 15:25 05 Feb 2003

Whatever it is, its very good info.

  MartinT-B 15:30 05 Feb 2003

Spyman - yes from CNET Glossary!!


You can't take advantage of the UDMA unless you know that your MoBo and system support it.

It seems to me that IDE will be fine.

You can buy the new Western Digital Caviar HDD with 8MB of Cache, running at 7200 for less than £1.00 per Gigabyte. The 8MB cache also lowers the 'seek time' - most HDDs have a 2MB cache

All the reviews I have read compare the Caviar very favourably with SCSI ( which runs at 10-15000 rpm).

  Mr Scone 15:34 05 Feb 2003

Yes you should look for at least 80gb UDMA 7200rpm. Go for Maxtor or Western digital. Failing that go for Seagate. Never ever get a IBM Deathstar, oops, i mean deskstar! ;0) They may be cheaper but I wouldn;t risk my data on their bad reputation


  bliksem 15:36 05 Feb 2003

Thanks for your help, I will look out for the WD Caviar.


  MartinT-B 15:36 05 Feb 2003

Caviar click here

review click here

  bliksem 15:37 05 Feb 2003

Thanks for your posts. Great price MartinT-B.



  temp003 05:26 06 Feb 2003

You need to get an IDE hdd with UDMA. They are different things, but not mutually exclusive.

IDE (or ATA) is now more commonly used to refer, loosely, to just the interface (connection) between the hard disk and the motherboard. The IDE connection is a standard item for PC’s. Most internal hdds and CD drives for PCs on the market are IDE devices (as against SCSI).

For practical purposes, you can ignore the term "IDE" as a limiting factor in terms of speed or capacity, in choosing your hdd, as long as you do get an IDE hdd.

UDMA is a mode of transfer of data between the hdd and system memory that bypasses the CPU (hence “direct memory access”). It is a transfer mode supported on the IDE interface.

The most common UDMA now is UDMA-100, max. 100MB/s. There is also UDMA-133, but it has no real performance advantage over UDMA-100. You may also see references to Ultra ATA-100, or Ultra-100. They are loose terms referring to the same thing.

UDMA hdds are backward compatible, but since your motherboard supports an Athlon XP 1600+, it’s likely it will support UDMA-100. For the same reason, it should have no problem recognising a hdd size of 80GB.

Going against the tide, also consider IBM/Hitachi's latest Deskstar 180GXP series (the 80GB model) that uses a “tag ‘n seek” technology rather like SCSI which reduces the seek time and is supposed to be very efficient.

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