AMD's SB850 and the PATA controller?

[loophole]

Just a curiosity question really but one that I can't find a good answer for ;)

In all the hardware review sites that discuss AMD's 800 series chipsets I've seen the same block diagram over and over again that shows the SB850 with a single PATA controller. Here's a good one:


But all the boards that I've seen and the reviews that I've read (mostly of new 890FX boards) seem to be using an auxiliary third-party chip for the PATA controller (or they have no PATA port at all).

So, I'm wanting to know: why aren't motherboard makers using it? Are all the block diagrams wrong and AMD has actually removed the PATA controller from the SB850 as Intel did a few Southbridges ago? Or is there some issue with the SB850's PATA controller that prevents board makers from using it (like the USB problems on AMD's early 768 southbridges)?

Just curious really. I can see the logic behind not using the integrated GigE on the SB850 if it means they have to buy a whole different PHY just for their SB850 boards, when they've already got reels and reels of Realtek PCIe GigE controllers (Intels GigE controller on their ICH10 suffers the same fate and is rarely used); I just don't see why they wouldn't use the PATA controller if it's actually present on the chip, especially if it's the same as what was in the SB750/SB710...

Thanks!
(congratulations, you made it to the end of my rant :) )

[artdrivers]

Re: AMD's SB850 and the PATA controller?

I dont quite understand your rant. It is in the AMD SB850 chip and used on the motherboards IDE/ATA/UATA connector. The Parallel ATA is used for optical disk drives or hard disk drives. The thing is there is only 1 of those connectors. http://en.wikipedia.org/wiki/Parallel_ATA
Is someone confusing this with a Parallel port? http://en.wikipedia.org/wiki/Parallel_port

[loophole]

Re: AMD's SB850 and the PATA controller?

Thanks for replying so quickly artdrivers!

I did warn that it was a rant, but I have to admit that even when not in rant mode I can be pretty incoherent, so I'll try again ;)

I've found many SB850 based boards that do indeed have a parallel ATA port, but upon further inspection the single PATA port isn't actually driven by the southbridge - in every board I've seen it's driven by an auxiliary third party ASIC. Here's a few examples:
* ASRock's 890FX Deluxe3 uses a VIA VT6330:
ASRock 890FX Deluxe3 Motherboard | Hardware Secrets
* Asus' M4A89TD PRO/USB3 uses a JMicron JMB361:
ASUSTeK Computer Inc.
* Asus M4A88TD-V EVO/USB3 uses a VIA VT6330:
ASUSTeK Computer Inc.
* Gigabyte's GA-890FXA-UD5 and GA-890FXA-UD7 both use a GIGABYTE SATA2 chip (which is actually a JMicron JMB363):
GA-890FXA-UD5 (rev. 2.0) - GIGABYTE
GA-890FXA-UD7 (rev. 2.0) - GIGABYTE
* MSI's 890FXA-GD70 uses a JMicron JMB363:
MSI Global ? Computer, Laptop, Notebook, Desktop, Mainboard, Graphics and more
* MSI's 890GXM-G65 uses a JMicron JMB368:
MSI Global ? Computer, Laptop, Notebook, Desktop, Mainboard, Graphics and more

That's probably enough ;)

I can't actually find an SB850 based board that has the PATA port actually being driven by the SB850. All the chipset block diagrams show the SB850 as having a PATA controller; why are motherboard manufacturers relying on third party ASICs instead of using the SB850's built-in PATA port?

Hopefully that makes more sense this time. If not I'm more than happy to go for a third try :)

[artdrivers]

Re: AMD's SB850 and the PATA controller?

Very well said now I fully understand. I'm sorry I was confused as to what you were expressing. I wasn't aware that some made desktop motherboards without a floppy connection which is on the AMD SB850, as well as the PATA, or any PATA connection.

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That could be as a big problem. We know that the majority are going to use the AMD SB850 SATA 6GB/s controller with their HDD's. As you said some have a seperate PATA controller.
By putting their PATA devices on the seperate slower controller which has already been added and team that with the SATA-DVD drives. Wouldn't this help with drive compatibility issues?

[loophole]

Re: AMD's SB850 and the PATA controller?

Yeah, the floppy connection on modern motherboards is finally (and slowly) starting to disappear. And like you point out, we're starting to see the first wave of AMD boards that are dropping the PATA port now too (some Intel boards have lacked the PATA controller for a little while now, as their ICH9 completely did away with PATA support).

Okay I think I understand what you're saying: in order to separate the slower devices from the faster SATA 6Gbit ones (whether they be mechanical hard disks or SSDs) you add a separate PCIe controller that will take care of the slower SATA (or PATA) optical drives and any ATA/133 (or slower) hard disks.

That makes sense I guess I just figured that the SB850's PATA controller would be isolated enough from the SATA controllers that it wouldn't be an issue, not to mention that you'd like to think each SATA port would be independent enough that a drive hanging off one port wouldn't interfere with drives on the other ports (I know, I'm probably living in a fantasy land ;) ). Forgive the possibly stupid question (I'm still on an SB600 based board (K9A2 Platinum) so I can probably be forgiven) but did they have trouble with drive incompabilities on the SB700 series of southbridges?

And so I guess if you're not so worried about it and you're trying to make a cheaper board, but you still want to provide a PATA port you buy a cheaper third party ASIC that doesn't have SATA ports (like VIA's VT6330 or JMicron's JMB368) and any SATA optical drives that the user wants can just live on one of the southbridge controlled ports.

I guess I'm just still a bit surprised that we haven't seen any boards using the onboard SB850 PATA controller, especially some of the cheaper boards where the manufacturer might not (how to put this gently...) care about drive incompatibilities (that's gentle enough ;) ).

So presumably stuff like this would go into some design recommendations document or something like that, that the motherboard manufacturers have access to.

Just as a tiny nitpick (and no disrespect meant), but the floppy controller is actually part of the Super I/O chip that's connected to the southbridge over the LPC bus, for example on Gigabyte's 890FXA-UD7 it's part of the ITE IT8720F Super I/O chip.

Thanks!

[artdrivers]

Re: AMD's SB850 and the PATA controller?

but did they have trouble with drive incompabilities on the SB700 series of southbridges?

Yes and also if you were to run a RAID setup. Wouldn't you be limited to some of the RAID features? If you had an ide sata dvd and the pata controllers all running at the same time? It is also possible they don't want to tax the southbridge chip controller with so many functions being sometimes utilized at the same time. What about voltage and heat? Therefore by installing another chip. Wouldn't this alleviate some of the load?
A bit off topic. These ITE EC-LPC I/O chips offer a robust amount of features which may not be fully implemented or utilized in the motherboards.
An example is the ASUS M4A89GTD Pro/USB3. It has the ITE IT8721 chip yet no floppy port. They may think that the floppy is a bit outdated and do not need to carry support for it, and thus a cost cut for the motherboard manufacturers. In the future this may be true, but as of now they are still being utilized. I think they are getting a bit ahead of theirselves. Most don't want to puchase USB floppy drives or slipstream their OS with RAID controllers. This small savings will probably result in a loss of sales. Also a larger expence on the cutomer service and technical support end. "Next no PATA?"
Well forgive me. Lets make it official. ♫ "I now have joined the rant." ♫

[loophole]

Re: AMD's SB850 and the PATA controller?

Yay! More people in on the rant :)

Okay then I can see advantages of having multiple controllers when drives don't behave well together. (I remember having more than a few problems with certain drives on the HPT366 controller of my Abit BP6)

Any device sitting on the PATA controller shouldn't have any effect on what RAID features the SATA controller portion of the southbridge can use, but you're right in that the more southbridge SATA ports you use for optical drives the fewer options you may end up with in terms of RAID levels and redundant drives etc (although this did get better when we moved from 4 SATA ports hanging off the southbridge to 6).

I would be really surprised though if installing the third party controller was done to reduce the load on the southbridge. AMD southbridges (as well as their northbridges) are known for being very frugal with power and cool running. The SB850 in fact has a 6W TDP (or 4W depending upon where you read) and all the boards I've seen have heatsinks on the SB that can handle considerably more than that (and that's not even taking into account that most mid-to-high end boards have a heatpipe network connecting the heatsinks together).

You're right though in that the Super IO chips found on modern motherboards offer an amazing featureset. Most still include the full complement of two serial ports and one parallel port. In fact the Fintek F71882 on my board (which is already a few years old) has the following:
* one IEEE 1284 parallel port
* two UART ports
* keyboard controller
* floppy disk controller
* Serial Peripheral Interface (SPI) for bridging function to the BIOS
* serial infrared (SIR) support
* voltage monitoring
* temperature sensors
* fan controllers
* a heap of GPIO pins

I clearly need to start thinking more of the humble Super IO chip ;)

I have to admit, I still use my floppy disk drive every time I do a BIOS update (one DOS boot disk and one disk to hold the BIOS image and flash utility, copying them to a ramdisk before the flash process), but that's because my BIOS doesn't have a built-in flash utility. (I recently updated the BIOS on a newer Gigabyte board and used their built-in Q-Flash utility and it was very convenient - just put the BIOS image on a USB memory stick and it'll find it)

So if my new board has a built-in BIOS flash utility, I'm not too phased if my next motherboard doesn't have a floppy port (I've already slipstreamed my XP SP3 install CD; but like you say many have not).

My DVD-RW won't be happy if my next board doesn't have a PATA port though (if it's still going when that time comes). I do like the ability to plug in any old random IDE hard disk though, especially for testing components from older computers that I've set up for people. So I'm all in favour of PATA hanging around for a little longer.

P.S. I don't think it's possible for anything to be off topic in this thread :-D