The more the cores... the higher the latency...

[Thonex]

Hi guys,

I'm finally (after 4 years) upgrading my studio computers!!!

I'm having a DAW builder build me my PCs. They will both be based on the i7 Neheelam (sp?). One is a 4 core the other an 8 core. One with 8 gigs, the other with 12 gigs.

One thing the builder mentioned was that the more cores you have, the more latency you get because it takes longer for all the 8 cores to reconcile the processing distribution. So, with 8 cores you get a ton of CPU capability, but at a higher latency. At what latency are any of you running your 8 core machine at? 256 samples?

What's the lowest you can reliably run an 8 core at? Is there a linear correlation between the 4 and 8 core latency performance delta?

Do you have a 4 core? Are able to run at a lower latency?

Are 8 cores really better than 4 in this scenario?

Thanks for any help.

Cheers,

Andrew k

[TAFKAT]

Hey Andrew,

I'd seriously question who that DAW builder is giving you that advice ?

There maybe some added arbitration navigating the current multi socket architectures , but its not something that I have seen as detrimental since the first revision of the 5100/5300 Xeon series systems.

I reported on that widely a few years back.

The current i7 /Nehalem architecture is native Quadcore, has an onboard memory controllers and is using QPI ( Intels super fast interconnect technology) , to buss to the rest of the sub system, so the arbitration issues of dealing with multiple Cache / FSB's, and off die memory controllers is gone , not that it was really an issue with the Core 2 at any stage , nor the Dual Xeons from late 5100 / 5300 ( core/buss arbitration fix ) / 5400 series .

The low latency performance that has been achieved on the single socket Core i7 systems, will be equally achieved on the Dual Xeons , IMO, and the diminishing return as the latency drops, that in the past was in the vicinity of 40-50% , is around 20% on the current systems going from 256 to 032.

In other words, you could easily set and forget at 064/128 , and have minimal to no impact to Real World Performance compared to 256 or above.

That is without DSP cards however, if you are using DSP cards, then there is a fine balance of where it goes all pear shaped.

Hope that helps.. :D

[Thonex]

Thanks Vin!!

That's good news for me then. Anyway... I'll post all my stats and whatnot when I'm finally up-and-running.

Kisses...
Andrew k