Macpro3,1. The last FSB of its kind. FSB vs QPI, major difference?

[Korican100]

So I have a Macpro3,1, decked out nicely. But I always feel behind because of FSB.

Can someone tell me how MUCH slower I am with a FSB over QPI?
Are there any pros if any using FSB. Any drawbacks of QPI?

What are the major speed difference in QPI? And in what practical applications would I see these speed increases using QPI over FSB?

 

[mif]

Memory intensive applications like Nehalem, i think.

 

[pastrychef]

I think Wikipedia explains what QPI is better than I ever could.

Here, you can see how different bus speeds can affect graphics cards. That's not the only thing that bus speeds affect, but it is the best example that I could think of off the top of my head.

 

[Korican100]

I think Wikipedia explains what QPI is better than I ever could.

Here, you can see how different bus speeds can affect graphics cards. That's not the only thing that bus speeds affect, but it is the best example that I could think of off the top of my head.

wow thanks for that barefeets link. I have the GTX680 in my macpro3,1. It says I would get double the performance out of it if I had a 5,1!

Jeeze louise!

FCPX feels fast on my machine, so I can only imagine how it would feel on 5,1!

 

[pastrychef]

I started to realize that bus speed was becoming an issue when I switched out my GTX 285 for a GTX 670. That was when I got a 5,1 to replace my 3,1 and got a GTX 680. Everything has felt a bit snappier. But it could well be a placebo effect...

 

[Korican100]

I started to realize that bus speed was becoming an issue when I switched out my GTX 285 for a GTX 670. That was when I got a 5,1 to replace my 3,1 and got a GTX 680. Everything has felt a bit snappier. But it could well be a placebo effect...

so its not a "very noticeable" speed increase?

 

[pastrychef]

I think I notice it, but, again, it could just be my imagination because I don't have any hard numbers to show.

 

[MacVidCards]

Note that BMD doesn't encourage Resolve to be used on 3,1 for this very reason. They even have a "If you must use a 3,1, we have these lowered settings for it" handicap to get useable frame rates while working.

I still love my 3,1 but it is the "bottleneck" in the machine.

 

[BJonson]

I just went from a 3,1 to a 5,1 and immediately felt the difference.