ATA100 vs ATA133

[wolvereen]

How much of a performance diff will I see on an ATA133 drive vs. an ATA100?

I have 3 ATA133's and 1 ATA100.

My MB (Asus P4C800) has a Primary and Seconday ATA100. IT has onboard Promise raid that can double as an ATA133 Tertiary channel. In addition I have a Promise
ATA133 card.

Should I:

A) Just keep my OS on the ATA100 and run off my Primary IDE channel for OS? I assume that doing this will make EVERYTHING run at ATA100 as the lowest drive factor is dominate, right?

or

B) Install my Promise IDE card, set it to Primary Boot device. Use that and the Tertiary on board for my ATA133 drives, then connect my ATA100 and CD drives to the boards Primary and Secondary channels? Doing that will mean I will have 4!!!!!! IDE channels! But will that mean better performance since my OS and main drives will be 133?

So have any of you seen any real difference in OS speed from ATA100 to ATA133?

Thanks!

 

[sjonnie]

The only difference in speed between ATA133 and ATA100 is the burst speed from the drives cache. This won't significatly improve your drive's or OS performance which is why no other manufacturer than Maxtor (who developed ATA133 in order to circumvent the 137GB barrier) use it. It is also why a SATA interface (150MB/s) doesn't increase drive performance over ATA100 interface (100MB/s).

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[Crashman]

The first guy is right, the only time your drives could exceed 100MB/s is from cache burst. And even those don't come to 133MB/s, because the interface isn't that efficient. Your ATA133 drives likely transfer data at a leisurely 45-66MB/s (maximum) from the disk platers, and probably around 105MB/s from cache.

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[sjonnie]

One reason why the bus doesn't transfer at 133MB/s is in fact because it is not capable of doing so. The M in Mega Bytes (MB) stands for 2^20 which is not quite the same as 1^6 (it's larger 1,048,576 vs. 1,000,000). That's one of the reasons why your hard disk always comes out smaller when it's formated and is also why the PCI bus actually transfers data at 127MB/s. Then as you rightly point out, there are efficincy losses which drop the rate down even further.

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[Codesmith]

You are wrong on that one. Bus speeds are aways given in true (binary/2^10) MBs. RAM capacites, and cache capacites are also measured in true MBs. The only place you see decimal MBs and GBs is with hard drives and removeable media.

Hard drives originally measured in binary GB, then one company redefined the GB to mean exactly 1 billion bytes. Then everyone else decided to copy them.

One flash memory maker tired to switch to decimal MBs, but the reaction was negative enough for them to hastily withdraw such a cheap marketing scheme.