NT4 and ATA66 drives

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Joined: Apr 1 1999

I spend an interesting time this summer getting a new PC up and running for a DVraptor test under NT4. Basically after much research I have found the following to be usefull:
NT's support for ATA66 in the standard driver seems to have problems (Even with SP5). Even if you use the MSutility to enable DMA what you probably will find that in fact PIO is being used instead of ATA66 mode.

Seems to be a combination of things:
You need the 80 Wire 40 pin cable
The drive needs to be in 66 mode, and the mother board needs to have correct 66 mode.
A series of calls to IBM, Maxtor Fujitsu etc reveals that not unlike DOCSolly's experience with large drives, the drives are way ahead of the OS and Bios/MB. SO IMO if you want to run ATA66 under NT4 get a Promise Ultra66 controller.
This allows you to get around all the silliness in NT where it will force a channel to operate at the rate of the slowest device, etc etc.

NOTE if you have a drive in 66 mode and your controller thinks in 33 mode, under NT it fails to give the proper response to the driver and switches to PIO mode.

With a 600 PIII, 512Meg Memory NT4 Sp5 Raptor test on an IBM 25g,Maxtor20g Fuj13g the best rate was 4.7m with Promise Ultra66, speed is all well up in the 13-14m range.

NT has always lagged in IDE drivers, in fact you find the IDE support under SCSI, SO be aware of the above. I had a few friends check a number of NT4 systems, and first they said NO way, but after checking those Ultra66 controller orders were sent in pretty quick.


Joined: Apr 1 1999

Just saw an interesting approach.
it seems that after you run the DMA enable utility from Microsoft you NEED TO RE RUN SP5.I have not personally tried it yet (I don't want to rip my system apart) but a few folks have and it seems to work.

SO If you have Ultra dma33 drives or Ultra Dma66 drives that you are reverting back to Ultra33 when you run the dma enable routine in NT you MUST RE RUN SP5