2x Opteron boards with 2 memoroy banks vs one ...

[AluminumStudios]

Some workstation dual Opteron boards have one bank of memory: http://www.tyan.com/products/html/tigerk8w.html

The higher end ones have separate banks of memory for each cpu: http://www.tyan.com/products/html/thunderk8spro.html

Can anyone tell me what the memory performance difference is? I understand that if each CPU has it's own ram, one cpu can access the other's ram through the Hypertransport link. What about when they have one bank of memory? Do they share it? Is there less total bandwidth between the CPUs and RAM?

Also, I thought I saw on a Tyan board a jumper that could be used to switch one of the PCI-X slots into a PCI slot. Can that be done or was I imagining it? I would like to get the 2nd Tyan board I linked to for a project at work, but I also require DVI and sound on that machine. I can't find any PCI-X video cards, so I'd have to try and find a PCI video card with DVI (video performance isn't that important, I just need DVI.) But that would use up the only PCI slot and I need sound ...

 

[Markfw]

Go with the 2885, it has an AGP slot. I didn't read the manual, and I am at work, but I think you can use a regular pci card in a pci-x slot. (maybe a jumper to set it to 33 mhz) Anyway, there is one regular PCI slot on the 2885, and you can use a AGP video with DVI, and it has two banks of memory (more memory, and both cpu's can run dual channel).

 

[AluminumStudios]

What's the difference between SSI EEB v3.0 footprint and Extended ATX? I need the board to fit in a tower case (the one I want supports up to Extended ATX.) That's why I hadn't looked at the 2885 ... I didn't think it would fit any standard Extended ATX tower cases ...

 

[Markfw]

I don;t know what SSI EEB v3.0 foot is, but the 2885 is a BIG motherboard, so make sure to get a BIG case. 24 inch x 24 inch or so. I don't like the Lian-Li case I got since it has very poor cooling though, so I can;t recommend a good one at the moment


this one looks promising. Make sure you get a EPS power supply for that mobo.This Antec one will work

 

[Steg55]

Since each Opteron has its own dual channel memory controller (~6.0gb/s @ PC3200) then two memory banks would give ~12gb/s memory bandwidth right? Instead of the 2 CPUs having to share the ~6.0gb/s from one memory bank (like Xeons). I don't know what the performance difference would be for 2 banks over 1 but I would think it would be substantial.

Yeh the 2885 would be a better perchase. Stick a 6800 in it and game like never before. Assuming you can find a SMP compatable game....I heard somewhere that HL2 was multithreaded but that might well have been intel marketing talk for 'works better on P4'.....I don't know

And anyway - 'Ive got dual dual-channel' sounds good

Steg

 

[ColdZero]

In all actuallity, for personal stuff, you won't see a difference in 6gb/s vs 12.

1. The opterons are not bandwidth starved processors
2. How much do you do that will need to throw around 12gb/s?

I recently purchased a dual opteron board that had seperate banks for each processor. Looking back on it, I wish I got one that had 1 bank because of the smaller form factor. The money I had to spend on a new P/S and case was for more than any monetary value I'd get from having an extra 6gb/s.

 

[AluminumStudios]

This machine is for a faculty member at work who needs to run machine learning software. This software will be hitting the memory hard and sensitive to both bandwidth and latency. I need to get this machine into a tower though, that's why Extended ATX is the max. I want internal sound and DVI video, so 2 PCI slots of a PCI and an AGP slot is important. I'm still trying to confirm if the PCI-X slots can support PCI cards. The documentation for these Tyan boards indicates there is a jumper to run a PCI-X slot in PCI mode, but I want verification of that before I try it ...