i7 and multi-GPU scaling.

[OzzmanFloyd120]

It's no argument that since the introduction of the i7 core CPUs that there's been a leap in scalability of having 3-4 GPUs. This makes me curious though as to why the GPUs scale so well. It's been suggested that it's the memory bandwidth, and it's also been suggested that it's having so many threads, but I find this hard to believe because the former could be acheived by OCing the AMD64 line of CPUs and the latter never revealed any results from moving to one to two to four threads.
My belief is that the scaling power doesn't lay in the CPU itself or even the memory controller, I believe that it has far more to do with the x58 chipset's architecture.
I just want to see what you guy think in this matter. Maybe we all might learn something.

 

[Binge]

The architecture of the chipset is pretty much dedicated to the PCI-E/peripherals instead of dealing with memory interface and PCI-E/peripherals.

Agreed. It's the chipset architecture.

 

[trickson]

It's the architecture .

 

[OzzmanFloyd120]

Architecture... of which? The CPU or the chipset?

 

[trickson]

Architecture... of which? The CPU or the chipset?

The CPU and the Chipset . Both !

 

[Solaris17]

banking on chipset arc...which is why i cant wait to complete my build....mobo and ram needed. 2 GX2's in quad sli....sweeeeeeet.

 

[CrAsHnBuRnXp]

Just so everyone knows, I was the one that voted "who cares, as long as it works."

 

[farlex85]

I would imagine QPI's added bandwidth perhaps gives it an edge over fsb? So it would be both a and b, actually b is really a, unless you are referring to the x58 in particular.

 

[OzzmanFloyd120]

I would imagine QPI's added bandwidth perhaps gives it an edge over fsb? So it would be both a and b, actually b is really a, unless you are referring to the x58 in particular.

Yes, I'm referring to the x58 specifically.

 

[James1991]

Just so everyone knows, I was the one that voted "who cares, as long as it works."

i'm the second

 

[farlex85]

Yes, I'm referring to the x58 specifically.

Ah, well then I voted wrong sorry.

 

[CrAsHnBuRnXp]

i'm the second

Im the type of person that doesnt care how it works I just want it to the way its supposed to. Once I set soemthing up, I could care less from there. I did my thing. Let it do its.

 

[James1991]

Im the type of person that doesnt care how it works I just want it to the way its supposed to. Once I set soemthing up, I could care less from there. I did my thing. Let it do its.

 

[X2-3800]

I7 is as fast as the old Q9xxx if you test it at the same clock, Turbomode off(overclockingCheat), and Hyperthreading off. Hyperthreading is useless if you have software that don't use it.
QPI and the integrated Memorycontroller don't bring much more power, because of the big caches.
Many sources said that in the most games the new I7 brings not much more power.
(cause of the lag of multicore and hyperthreading support)
The I7 is overkill for people wich only playing games or doing office work.

"My belief is that the scaling power doesn't lay in the CPU itself or even the memory controller, I believe that it has far more to do with the x58 chipset's architecture."

I think so, too. The only real reason for the GPU scaling can be the chipset and its PCIeX performance.

 

[[I.R.A]_FBi]

I7 is as fast as the old Q9xxx if you test it at the same clock, Turbomode off(overclockingCheat), and Hyperthreading off. Hyperthreading is useless if you have software that don't use it.
QPI and the integrated Memorycontroller don't bring much more power, because of the big caches.
Many sources said that in the most games the new I7 brings not much more power.
(cause of the lag of multicore and hyperthreading support)
The I7 is overkill for people wich only playing games or doing office work.

"My belief is that the scaling power doesn't lay in the CPU itself or even the memory controller, I believe that it has far more to do with the x58 chipset's architecture."

I think so, too. The only real reason for the GPU scaling can be the chipset and its PCIeX performance.

i5 is just right then?

 

[X2-3800]

i5 is just right then?

http://www.hardware-infos.com/news.php?news=2571
Sorry for german laguage. They say that the massiv memoryperformance is at most useless.

I think I5 is the better choice, it have only two memorychannels and is for sure less expensive than the I7. That should drop the price for the mainboards, too. Currently you have to pay >230€ till over 300€ for one I7 mainboard!

With I5:
1. You need no expensive 3 channel memorykits.
2. Mainboards are much less expensive because of
"Sockel mit 1156 statt 1366 Kontaktflächen " > Sockets with less Pins >less costs at
motherboard design.
3. less memorychannels > less power consumption

The draw back is the decreased memoryperformance, but the DDR3 memory can only get faster with the time. Timings are going down and frequencys going higher.

 

[rizla1]

ddr3 hardly consumes much powerdoes it, id be happy with i5 still got 8 treads . i do 3d work photoshopings and heavy multitasking so would benifit from it even and just overclock it.

 

[DarkMatter]

I think it's primarily the fact that they moved the memory controler to the CPU (that also made A64 fly) + more and far better caching system + improved latencies + better prefetching + better thread hadling + ...

i7 improves so many things, it can't be just because of one. In one article I read in Real World Technology about CUDA but that explained GT200 too, they said that current generation of cards didn't perform as they should (2x the previous one) because the CPU couldn't generate all the required threads without introducin lag.

Also I strongly believe in the possibility that PCIe 2.0 was improved in the X58. Just because a chip follows one standard it doesn't mean it can deal with it 100% effeciently. Just as with memory, you can use PC11200 memory but that doesn't mean the chipset will deliver that.

 

[lemonadesoda]

I think there is a combination of:

1./ Improved drivers of the GPU
2./ Ability for QPI to allow competing demands on system memory (both CPU, GPU1 and GPU2) to be simultaneously serviced. Remember that if you have 2 GPUs you need to load ONE asset TWICE. Therefore 2GPUs have double the memory bandwidth demand. GPU2 cant draw until BOTH GPU1 AND GPU2 have loaded the asset.

I think i5 might not scale as well with 2 GPUs due to point 2.

A larger GPU memory (more cached onboard and less use of system memory) would reduce the effect of 2.

Therefore 1GB or 2GB boards would scale better than 256MB or 512MB.

Somebody with 2x Quadro FX4800/5600's, an i5 and an i7 can prove this theory.

ANSWER: DDR3 + chipset + QPI architecture

Where is my option in the poll? Doh!

 

[The Haunted]

I guess its the chipset as there is a massive improvement in crossfire scaling from p35 to p45.
http://www.tomshardware.com/reviews/crossfire-pci-express,2095-7.html

 

[kid41212003]

It's because even the Yorkfield couldn't draw ALL the powers of 3 of 4 GPUs.

More GPUs require more CPU powers.