Acolyte of the Butterfly
Posts: 105 from 2003/2/10
From: Lightning capi...
let's address this in-order
Quote:
Donar wrote:
l>by Kronos on 2003/12/28 1:32:46
>1st they have to see what chips they can actually get and use from Marvell,IBM
>and VIA, than their options will be reduced to what these offer.
Good point. In the interview on GIGA TV one of the developers said that they will include Serial ATA IF it is succesfully introduced (or something like that). So they were not sure IF they should include it rather than HOW to include. And that is the reason i posted this in the Guest House and not Silicon Grill. Let them hear our suggestions. Most of the things mentioned here can be done. One thing that seems difficult to me is the Dual Proc option. Dual Proc Boards in the x86/AMD64 world are mostly E-ATX and Expensive. Maybe Genesi can make it better?
Can't hurt to try
Quote:For the available options chip wise let`s have a look what Marvell can offer:
Marvell plans to extend its market-leading family of Discovery™ chipsets with new system controllers that include IBM's high-speed PowerPC 970 Elastic Interface technology.
Marvell's Discovery 970 system controller is intended to provide embedded customers with a comprehensive and cost effective 64 bit sub-system solution. In conjunction with Marvell's Gigabit PHY, Serial ATA and high-speed switching products
The Discovery 970 system controller integrates several I/O peripherals on-chip, including Gigabit Ethernet, PCI-X bridges, storage functions and DDR memory interface.
Marvell plans to make samples of its Discovery 970 chipsets available in the first quarter of 2004.
Marvell Press Release So,
PPC 970
ElasticInterface
PCI-X
GigEthernet
DDR Memory
all possible, no mention that the DDR controller will be dual channel, but if not they would cripple the 970 (right?).
Not necessarily. There are alternative DDR concepts, including a *wider* DDR bus, 128-bits rather than 64-bits. (So you'd have to double-bank things) Dual-channel is one option popular in the x86 world, because a wider bus would not benefit them as much. But for PPC, wider is a serious option that gives full benefits. Not saying this is what they are doing, just saying it is another option other than dual-channel. There is also DDR-II technology as well, don't forget.
Frankly, this is an area where you can guess yourself around in circles
Quote:
No mention of AGP or Hypertransport. As a modern controller it should really handle AGP 8x in one or another way.
Why? AGP 8x is already a technology 2 gens behind, slower than PCI-X 2.0 as well as PCI-Express and Hypertransport. The key is not to support the speed, which is wasted 99% of the time, but to support the cards voltages. Combine the crossbar's bandwidth with the improved latency found in the backbone for the system, and even a slower AGP will actually do its job faster. Remember, those numbers (8x, 4x, etc) refer to *peak* performance, not total thuroughput. If your AGP 1x can maintain 1x speeds constantly, while your 8x is fluctuating wildly, guess which one will be faster in the end?
Quote:
In AMD 64 World they take a Hypertransport linked AGP subsystem "AMD-8151 HyperTransport AGP3.0 Graphics Tunnel" for that.
Ever checked out the latency there? With 4x the potential performance of the AGP 2x card I run on my Athlon, it gets only 5% higher performance. The latency of this arrangement is absolutely horrible, eating up any potential.
Quote:Post is long enough, (to all) your turn.
<edit>
Nothing to do in the morning, all are asleep except me. So i did a quick search and found out that Marvell is member of the Hypertransport Consortium.
Klick MeSo they could include Hypertransport links as well. From then Genesi could buy standard parts for eg. AGP.
</edit>
If they include HT links, sure, but they're running PCI-X, which now has better bandwidth than HT (2 to 1 with the latest PCI-X spec) and doesn't require new components to work.
Remember, as of PCI-X 2.0 (the Peg 2's northbridge is 1.x before you get any ideas) the peak speed of PCI-X is now 533Mhz. 64-bit @ 533Mhz, you do the math.
Nate Downes
Genesi SARL