AMD DX 11 Evergreen to be unveiled Aboard USS Hornet

apoppin · Posted: Sun Aug 23, 2009 10:33 am

gstanford wrote:

I'm not sure what p55 motherboard I'd go for yet, probably not an MSI though, have had too much MSI product stuff up in the past to even consider them. They are just a more expensive PC-Chips in my book (in fact their main competitor is ECS (PC-Chips)).

The nForce200 on certain boards I'd actually consider to be pretty irrelevant, since it only expands communication between the slots, not back to the CPU.

I did notice that there are 8 PCI-e lanes in the P55 chipset, but two are used already, and the remainder seem to be used for implimenting the 4x slot. There is some small hope I guess that intel will expand the number of lanes in a future chipset, but that doesn't help today.

This is a situation where I'd actually recommend a Geforce295 (or a 4870 x2) along with a board that has one 16x PCI-e slot and one 4x PCI-e slot. I don't think 3 slots buys you anything useful and the P55 platform and you would be wasting your time and money with multicard SLI/Crossfire.

are you sure about the bridge?

MSI uses 3 x 16x PCIe slots in their top P55 mobo; 2 x 16x PCIe in the P55 i linked to

Quote:

Apart from the Intel P55 PCH, it uses an NVIDIA nForce 200 bridge chip that broadcasts 16 PCI-Express lanes (from the processor root complex) to 32 lanes on the PCI-E x16 slots

gstanford · Posted: Sun Aug 23, 2009 11:17 am

Yes, I'm sure. When the CPU talks to the PCI-e slots it does so at 8x when in SLI/Crossfire mode. This is because the CPU only has 16 PCI-e lanes integrated into it and for SLI it splits that into 2x 8. The nforce200 chip takes the 16 lanes and expands them to 32 lanes, but only between itself and the PCI-e slots, so any SLI traffic that is GPU to GPU will happen at 16x since the cpu isn't involved (remember nForce200 is also a PCI-e switch chip and can reroute traffic on the PCI-e bus, which speeds SLI GPU communication up -- a fact conveniently overlooked by the fanatics when they bitch and moan about SLI being a locked technology and falsely claim that there is no hardware involved with SLI that other PCI-e implimentations lack, fact is that there is and has been since nForce7).

Read what Anand has to say on the subject if you don't believe me:

http://www.anandtech.com/mb/showdoc.aspx?i=3623&p=2

Quote:

As I’ve mentioned in the past, Lynnfield includes an on-die PCIe controller provided 16 PCIe 2.0 lanes. Using an external switch those 16 lanes can be split off into two x8 slots, enabling CF and SLI (CF is enabled free of charge, SLI requires participation in the licensing program).

Although unnecessary, if you want the bandwidth of two x16 PCIe 2.0 slots the motherboard manufacturer will need to use an nForce 200 chip. This chip houses 32 PCIe 2.0 lanes but connects to the Lynnfield chip via 16 lanes, so you get better bandwidth between cards but no increase in bandwidth between the GPUs and the CPU. Expect boards that use an nForce 200 chip to be limited at best.

apoppin · Posted: Sun Aug 23, 2009 11:21 am

thanks for the clarification; the bridge chip does give better bandwidth between cards but cannot increase bandwidth from the CPU
- i guess that is the trade-off intel made to integrate the PCIe controller on i5; slightly lower latency at the expense of crippled bandwidth

it looks like i7 may be in my future - after i do some testing with 8x PCIe vs 16x

gstanford · Posted: Sun Aug 23, 2009 11:41 am

I don't know if the same limitation i5 & i3 have will apply to socket 1156 i7's. maybe they will get 32 lanes.

Anyway, you now see why I prefer (old) i7 to i5. Pretty silly considering the competing AMD chipsets which will be i5's main competition all have options for full blown 2x 16 PCi-e. Still it decisions like this that ultimately allow AMD a little breathing room.

apoppin · Posted: Sun Aug 23, 2009 12:08 pm

gstanford wrote:

I don't know if the same limitation i5 & i3 have will apply to socket 1156 i7's. maybe they will get 32 lanes.

Anyway, you now see why I prefer (old) i7 to i5. Pretty silly considering the competing AMD chipsets which will be i5's main competition all have options for full blown 2x 16 PCi-e. Still it decisions like this that ultimately allow AMD a little breathing room.

thanks for making that a bit clearer
:good:

down the road, full 2 x 16x PCIe will be important; how soon, i cannot say - clearly i will be upgrading pretty often; but i wonder about this coming GT 300 and HD 58XX series
.. i have to make a decision in the next couple of weeks :blush:

gstanford · Posted: Sun Aug 23, 2009 12:19 pm

I was going to say, for all we know GT300 could be the PCI-e 2.0 tipping point. GT200 was certainly the PCI-e 1.1 tipping point, as I found out first hand with nForce5 & 7.

GT300 is mere months away.

apoppin · Posted: Sun Aug 23, 2009 12:26 pm

gstanford wrote:

I was going to say, for all we know GT300 could be the PCI-e 2.0 tipping point. GT200 was certainly the PCI-e 1.1 tipping point, as I found out first hand with nForce5 & 7.

GT300 is mere months away.

agreed; that is what i am concerned about

GTX 280 needs more than 4X PCIe; that was one of my first reviews here
- however, it would mean that GTX 380 would need to almost double GTX 280's bandwidth to saturate the 8X slot - that is a rare generational leap that accomplishes this - of course, i am looking forward to fast GPUs with 2GB of vRAM as 'standard'

digitalwanderer · **Joined:** Tue Sep 08, 2009 1:04 pm **Posts:** 1

Aw, you guys won't be there? And here I was hoping I'd finally meet the three of you. #:-S

apoppin · Posted: Tue Sep 08, 2009 7:04 pm

digitalwanderer wrote:

Aw, you guys won't be there? And here I was hoping I'd finally meet the three of you. #:-S

*The* digitalwanderer ?
=D>

Welcome to ABT!
:good:

Nope, we are not on AMD's invite list yet. :blush:

ABT's first year anniversary is this coming October 1st - So, there is plenty of time for us to prepare for next year and i hope to be able to make these events and to meet you
:hello:

AMD DX 11 Evergreen to be unveiled Aboard USS Hornet

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