Can anyone explain this?

[MF]

"As the disk drive market gradually moves to the Ultra DMA66 specification,most motherboards are still not capable of supporting this new standard due to the limit of current chipsets.
The Hot Rod 66 card can be used with any board and although the BX chipset was designed to be compatible with the Ultra ATA/66 specification,it is only capable of running at a maximum of 33Mbytes/sec, thus offering no advantage over UDMA/33.With the help of the ABIT Hot Rod 66, your mainboard can support this specification at its intended 66 Mbytes/sec of date throughput. The result is maximum disc performance using the current PCI local bus environment."

I got the above quote from ABIT HotRod 66 web page. Can anyone explain this? If mobo doesn't support UDMA66, will using Hot Rod 66 change that? As far as I know, mobo has to support UDMA66 so that UDMA66 controller and devices can be taken advantage of but the above quote confuses me. Thanks.

[LJE2]

When you install a card like the Abit HotRod or the Promice Ultra DMA 66 card you are connecting your hard drive cable to the IDE connector on one of these cards and using the hard drive controller chip that is onboard the card instead of connecting the cable to the IDE connector on the motherboard and using the controller chip that is on the motherboard.

By using the Abit HotRod 66 card on a motherboard that does not support Ultra DMA66 you will be able to take advantage of the slightly faster burst speed and transfer speed of a Ultra DMA 66 hard drive. I say slightly faster because although the burst speed is twice as fast as Ultra DMA33 the actual sustained transfer rate is not much faster.

[MF]

Thanks for your explanation. I've read it somewhere too about the small advantage of UDMA66 over UDMA33.
Just only these two or other cards in the same class can do the same?

[LJE2]

All Ultra DMA66 cards are about the same in performance, the slight difference between Ultra DMA33 and Ultra DMA66 is not the fault of the controller card, it's the hard drives, they aren't capable of much faster transfer speeds, although the Manufactures are building faster ones everyday, I just read about a Maxtor drive built for the Ultra DMA100 standard, and it was considerably faster than UDMA 66 drives. When this standard becomes available and the drives become available I think we'll see a big improvement in hard drive speed.

[Peter M]

Just putting a few things straight ...

The Intel 440BX chipset, the PIIX4(e) south bridge part to be exact, does NOT support UDMA66 on its integrated IDE controllers.

This does not keep anyone from connecting an add-on PCI device that does UDMA66. PCI bandwidth of 133 MB/s easily allows that.

Like SCSI adapters, those add-on UDMA66 IDE controllers come with their own BIOS that handles whatever they have attached - so this is where the UDMA66 BIOS support comes from.

Faster bus transfers on IDE drives aren't so much about increasing data throughput - the greater benefit is that such a controller can use the PCI bus more efficiently, freeing PCI bus bandwidth for other tasks. This means drive performance as measured in benchmarks won't increase much, but overall performance in applications that move a lot of data, like video processing, can increase noticeably.

Regards, Peter

[MF]

Thanks.