Speed

[tmlim]

Can't remember where I got this from:

Interface, Theoretical Bandwidth, Practical Bandwidth
USB 1.1 (alt), 12 MBit/s, 1 MByte/s
USB 2.0, 480 MBit/s, 25 MByte/s
IEEE 1394A / Firewire400 / i.Link, 400 MBit/s, 30 MByte/s
IEEE 1394B / Firewire800 / i.Link, 800 MBit/s, 60 MByte/s
Serial ATA, 1500 MBit/s, 120 MByte/s

What would be the data for IDE Drives.?

"A delayed game will eventually come out, a bad game is bad forever."
-Shigeru Miyamoto

 

[folken]

All drives except maxtor are ATA100 there for they are 100MBit/s or about 12.5MByte/s. Maxtor drives are rated at ATA133, 133MBit/s or about 16.6MByte/s. That doesn't sound right but I think I'm close, I havent delt w/ ide stuff in a while

<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>

 

[Crashman]

NO, ATA100 standard for 100MegaBYTES per second. USB, Firewire, Network connections are measured in Megabits, hard drives in MegaBYTES.

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>

 

[Crashman]

IDE drives are rated in Megabytes/s. So an ATA100 interface supports the full 100MB/s, an ATA133 interface supports the full 133MB/s. However, the controllers aren't 100% efficient, so depending on the controller you might see 89MB/s through 100MB/s on ATA100.

The problem with hard drive interfaces is that they are much faster than the drive mechanics. Typical drives transfer around 60MB/s from the outer part of the platters, and 30MB/s from the inner part. They occasionally reach 100MB/s in cache burst, that is, when the 2MB or 8MB cache chip on the drive dumps data to the bus.

SATA150, same deal. 150MB/s for SATA1 is honest for the bus, but the drive itself is limitted by its mechanics. SATA150 drives have exactly the same performance as the ATA100 version.

Now, here's some math for you
USB 1.1 is measured at 12 megabits. There are 8 bits to a byte, so that's where you get 1.5MB/s as the theoretical limit. And overhead knocks that down to 1MB/s roughly
USB 2.0, 480megabits/8 is 60MB/s. But overhead and so forth cut that roughly in half.

So you see Megabits/8=Megabytes, and that hard drives are measured in MegaBytes/s (MB/s), while the external interfaces you mentioned are measured in Megabits/s (Mb/s).

<font color=blue>Only a place as big as the internet could be home to a hero as big as Crashman!</font color=blue>
<font color=red>Only a place as big as the internet could be home to an ego as large as Crashman's!</font color=red>

 

[folken]

That makes a whole lot more sense. I've been doin to much networking, prettymuch everything is in megabits

<A HREF="http://www.folken.net/myrig.htm" target="_new">My precious...</A>

 

[tmlim]

Thanks, Folken and Crash!
That clears a lot of things up!

"A delayed game will eventually come out, a bad game is bad forever."
-Shigeru Miyamoto

 

[FriedSpam]

well, you people seem to know what you're talking about and my questions is sort of related to this...

My Mobo is the GA-8IHXP (850E) which has PCI 2.2 complient slots.

If I've got it right, PCI 2.2 is PCI 2.2 is 33MHz and 133 MB/s (or is it 66MHz and 233MB/s???).

Well, I want to get a SATA RAID controller card for my pc and a few SATA drives to go with it. My worry is that if SATA drives transfer at 133MB/s and my MB's PCI slots transfer at 133MB/s I'll only be getting a transfer rate of 66.5mb/s for each drive on a PCI controller.

From what I've read in this thread, that doesn't seem to be the case. How many SATA drives could I put on one card before the speed of each drive is reduced due to the limits of PCI 2.2?

-or would I just be better off getting a 1 port sata controller for each SATA drive I get???

Thanks!!!!