Has anyone tested how a dual CPU board with dual core CPUs scales with SLI?

[g__day]

It might be pricy, but for benchmarking to see just how much CPUs might be holding back the new high end cards in SLI or Crossfire, has anyone yet tested a dual CPU board (e.g. TYAN's high end) using say two dual core AthlonFX 60s on top end dual gpu gear with a benchmark that caters for it?

I'd like to understand beter how much more headroom dual GPUs have if the CPU were to scale much higher through clockspeed or increased parallelism.

 

[Dave Baumann]

You'll need the applications themselves to make significant usage of increased CPU parallelism before you'll notice much difference from dual core over single, as this isn't "automatic" as it is with graphics. Even then, applications are not necessarily going to scale linearly with numbers of cores (i.e. Tim Sweeney suggested that the likelyhood for Unreal would be that there is a "core" engine thread, a graphics thread, possibly a physics thread (IIRC) and then several "helper" threads).

In many cases the gains for multi graphics on Dual core stya very similar to single graphics with the drivers drivers shuttling things like the general driver overhead, shader compiliation/optimisation and possibly some vertex shaders on to the second core with single threaded apps.

 

[obobski]

With more processors all your doing is increasing the total FLOPS of the system, your doing more work in the same time, however most software of today is designed to scale by linear clock speed: a 9GHZ Pentium 4 would be faster than 2 5GHZ Pentium 4's (this is purely theoretical)

Hopefully with the advent of dual cored processors this changes, and we get software that can utilize higher GFLOP output of the system, without needing it moving faster (in other words, most software appears to want the system to look at things in a scalar and serial way, and in order to get more performance we need to get software that wants parallel (and possibly vector) perceptions, then dual cores and SMP's can really kick ***)

 

[g__day]

Isn't that just a design question, hand work out using gaming middleware with put/get queues? That way you design becomes inherently parallel friendly and any idle unit simply line up getting work from a queue, doing it then getting more work.

These principles have been around since the eighties!

 

[g__day]

Interesting article here, titled Dual CPU or Dual Core?

http://www.pugetsystems.com/articles.php?id=23

Conclusion

As you can see, the move to dual-core is definitely a win for consumers. Since they are more affordable than dual processor systems, but offer the same or better performance, they are becoming the standard for modern computer systems.

 

[g__day]

A small bump as it appears AMD is going in this direction with its 4x4 mentioned today

http://www.extremetech.com/article2/0,1697,1970534,00.asp

AMD Announces Dual-Socket, Dual-Core '4x4' Platform

and

http://techreport.com/onearticle.x/10091