How much of the latency comes from the interface, how much from the CPU?

[AD Chaos]

Been wondering about this as I'm getting a new PC build and a second interface (a budget one, a Saffire 6 USB I'm thinking, paired with a new i7 960 build)..

However I'm not sure about the interface because of some recent posts in here with people complaining about latency issues with the Saffires, but I'm thinking it may be due to the computers, rather than the interface?

The main concern for this setup is going to be the best possible performance with sims, as I'm to recommend this same setup (PC+interface) for other people I teach guitar to, who are going to be on a budget (no real amp, etc).

FWIW, I have a FF800 pairing with a QuadCore Q6600 atm (6 or so year old build). Don't have very big latency issues usually, but I'm guessing a newer PC build could always improve things a lot?

Thanks much for your time and your opinions

 

[drew_drummer]

AFAIK, not a whole lot of it is down to the CPU. It's mostly down to the speed of the interface, and the speed of the PCI buss on the motherboard.

 

[AD Chaos]

and the speed of the PCI buss on the motherboard

Even for an external USB (or a Firewire) interface?

 

[drew_drummer]

Even for an external USB (or a Firewire) interface?

Yes. Even though its a USB or Firewire card, it still has to travel through the PCI buss!

 

[::XeS::]

And it depends also from the drivers.....my m-audio profire 2626 at 128sample buffer size is way slower than an rme at the same buffer size

 

[AD Chaos]

And it depends also from the drivers

Are drivers different in between different interface models of the same brand?

 

[AD Chaos]

and the speed of the PCI buss on the motherboard

According to this, the PC would matter, no?
I guess looking for that spec in a mobo is important, then.

It would be interesting to know if there's a general number or % in terms of how much each of the two components matter, for audio latency. I guess the easy/obvious way out would be the usual 'it depends'.. but still.

 

[::XeS::]

In my opinion latency is not related very much to the cpu....I get the same latency in my macbook pro and my hackintosh. Maybe a faster cpu can handle better lower latency, but at the same buffer size, the latency is the same.
About the drivers, it depends. Some brand has different drivers for different interfaces, other brands have the same driver version for every product

 

[voidar]

Check some ADK benchmarks:

http://www.adkproaudio.com/benchmarks.cfm

"Its interesting how well the last gen T9600 hung in there or beat the newer i5/i7 mobile.
It shows that GHz is still very important particularly at low latency, the biggest reason it didn't do well @ 48 buffer was at that point its more memory dependant and the newer systems with DDR3 1333 are outperforming the older DDR2 800.

Due to the 620m (dual core) being 2.66GHz it outperformed the Quads."