where are the promised PCIe x4,x8 slots?

[Brannon]

I want to build a certain hardware device that needs a minimum bus
speed of the PCIe x4 slot. I'd prefer the x8. I intend my device to be
complete 8 months from now and sell to consumers for a cost of $300.
It's an accelerator for some various kinds of software.

Here's the issue: the average motherboard sold these days doesn't have
an x8 slot! Most don't even have x4 slots. It's rediculous. I thought
all devices would be migrating to PCIe. It doesn't cost the motherboard
manufacturer's any more money to put PCIe on their boards. It's
apparently a problem with the chipset makers still feeling that 4 PCI
slots is preferred over 2 PCI slots and 2 x8 PCIe slots. Can that be
right?

In the meantime, should I build the device or not?

 

[Paul]

I want to build a certain hardware device that needs a minimum bus
speed of the PCIe x4 slot. I'd prefer the x8. I intend my device to be
complete 8 months from now and sell to consumers for a cost of $300.
It's an accelerator for some various kinds of software.

Here's the issue: the average motherboard sold these days doesn't have
an x8 slot! Most don't even have x4 slots. It's rediculous. I thought
all devices would be migrating to PCIe. It doesn't cost the motherboard
manufacturer's any more money to put PCIe on their boards. It's
apparently a problem with the chipset makers still feeling that 4 PCI
slots is preferred over 2 PCI slots and 2 x8 PCIe slots. Can that be
right?

In the meantime, should I build the device or not?

If your customers have SLI motherboards or Crossfire motherboards,
then you can use one slot for video, and the other slot for your
product.

You can see part of the problem here. The more common chips would
be the ones in the right hand columns. Not really good candidates
for x4 slots.

http://www.nvidia.com/page/nforce4_family.html

Also, you should be aware, that some motherboards that have a
x4 slot on the motherboard, only have x2 PCI Express lanes wired
to it. And the motherboard manual doesn't say something plain and
obvious like "hey, dummy, we only used x2 lanes". They say the
slot is "capable of 1GB/sec", which means they counted the 500MB/sec
of each direction and came up with a number the marketing people
could abuse.

The reality is, if your accelerator really needs x4, then you
are looking at using one of the slots on an SLI board. On
some motherboards, the original BIOS doesn't actually support
an add-in card in the slot, and it may take a BIOS update to
get it working. One Asus motherboard explicitly stated in a
BIOS release note, that now an Areca RAID controller would work
in one of the SLI slots. So again, the evidence that there
is support for your product idea, is buried deep.

Finally, there is your product pricing. The question is, who
has $300 to spend ? The "tone" of the add-in hardware market
has been set by $10 USB cards, and $20 SATA cards. It is a
steep uphill climb to get to $300. That is more than the
blow-out sale price of processors this summer. I think you
should realistically target your product at a corporate
market, which is less price sensitive. I've thought about
doing my own products, and this is the most significant
barrier to doing anything cool. Nobody would appreciate
your efforts.

As a teaser, here is a motherboard with x8, x8, and x4
wiring, all with x16 sized (universal) slots. The Intel Badaxe.
The latest revisions accept Conroe processors.

http://developer.intel.com/products/motherboard/d975xbx/index.htm

Here is another board in the "monster truck" catagory:

GA-8N-SLI Quad Royal (four x16 sized slots, with four x8 wiring)
http://www.gigabyte.com.tw/Products...oductID=1957&ProductName=GA-8N-SLI Quad Royal

The Quad Royal cannot really do 32 lanes worth of bandwidth,
since the Hypertransport bus is the limiting factor. I believe
the Hypertransport bus is the equivalent of 16 lanes worth.
This should also be a limitation for the SLI x16 boards which
use the same Nvidia chipset.

Apple Computer has also done something similar to the Quad
Royal. In Apple's latest computer, all the expansion slots
are x16 sized PCI Express slots. Of course the lane wiring
is not x16 (right off hand, I don't know how many lanes are
wired to each one), but the end result is you can stick any
kind of expansion card you want in there.

Paul

 

[Brannon]

Thanks for the fantastic response. I was thinking $300 because that is
barely over the sum of the parts. The only way I can make money at that
price is to buy my parts in bulk, which won't happen initially. Also, I
figure that nice graphics cards priced around $300 do sell, so maybe my
device would have a chance, especially if I get it into both the CAD
and game markets.

 

[DaveW]

You are too early in the adoption rate of PCI-E devices other than video
cards.

 

[Paul]

Thanks for the fantastic response. I was thinking $300 because that is
barely over the sum of the parts. The only way I can make money at that
price is to buy my parts in bulk, which won't happen initially. Also, I
figure that nice graphics cards priced around $300 do sell, so maybe my
device would have a chance, especially if I get it into both the CAD
and game markets.

You should talk to someone about distribution channels and profit
margins. (That is a chat I could benefit from as well.) I've
seen it written before, that the e-tailers of the world will
make all the profit, leaving you with peanuts. If you are
thinking in terms of a small time operation, then direct
web sales will be a temptation. Of course, all your free
time would be spent packaging product, and if you tried
for world wide sales, you'd have to become an instant
customs and excise expert. Also, your country may have
business licenses for some of these things. And you also
have to watch for scam sales from certain countries famed
for scamming small time operations with stolen credit
cards.

While e-tailers suck, the compensation is, you line up your
production outfit to build, test and box. And then
all you have to figure out, is how to get the
e-tailers interested. But based on comments I've read
before about doing stuff like this, you will very
likely starve to death at first (you could be shipping
lots of product, but have nothing to show for it). And
if a large order comes in, the inevitable cash crunch
problem of pushing a big order through your assembly shop.

Good luck. If you happen to get rich doing this, post back

Paul

 

[spodosaurus]

I want to build a certain hardware device that needs a minimum bus
speed of the PCIe x4 slot. I'd prefer the x8. I intend my device to be
complete 8 months from now and sell to consumers for a cost of $300.
It's an accelerator for some various kinds of software.

Here's the issue: the average motherboard sold these days doesn't have
an x8 slot! Most don't even have x4 slots. It's rediculous. I thought
all devices would be migrating to PCIe. It doesn't cost the motherboard
manufacturer's any more money to put PCIe on their boards. It's
apparently a problem with the chipset makers still feeling that 4 PCI
slots is preferred over 2 PCI slots and 2 x8 PCIe slots. Can that be
right?

In the meantime, should I build the device or not?

A new-ish Dell at work has a 4x slot. I'm trying to source a NIC for it
in Australia at the moment.

Ari

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