Why can I get much lower latencies on my desktop than my laptop?

[Whoopysnorp]

I have two PCs: a desktop with a 1.8 Ghz Core 2 Duo used mainly for mixing, and a laptop with a 2 Ghz Turion X2 used mainly for tracking (I live in an apartment so I have to go to our rehearsal space to track loud stuff). I have them both running Windows XP SP2 with all the necessary updates, etc., and configured in the same way. I use the same audio interface (RME Fireface 800) with both of them, and I even use the same Firewire external hard drive with both of them. Both machines have 2 gigs of RAM. Why, then, am I able to use a 96 ms latency with no problems on my desktop, and my laptop seems to require a latency of over 768 ms in order to record ~10 tracks of audio smoothly? I have done all the important tweaks you're supposed to do, like optimizing for background processes, disabling write caching, etc. Any way I can squeeze a lower latency out of the laptop?

 

[Almy]

Laptops are a different beast. Everything from busses and irq's and the chipsets that run them (not your processor chip) to hard drive speeds and more. On top of that even the BIOS, which manages your hardware, is important. I'm not the one to be able to give you all the details but just a heads up that there is a lot more to it than just typical adjusting with laptops.

 

[Steve Henningsgard]

When companies make decisions on which specific chips to put into a laptop, their primary motivations (other than price) are size & power consumption, with performance and compatibility being less of an issue. With desktops, power consumption and size don't really matter as much, and so in general you can get higher-performance parts for desktops than laptops. That's not to say laptops = low performance! It just means you've got to take the manufacturer's motivations into consideration when purchasing a laptop (meaning: research exactly what chipset the manufacturer used for firewire in your laptop & things of that nature).

Desktops have faster video cards, processors, memory, hard drives, and overall performance available than laptops, due to the lack of size & power-consumption considerations.

(Disclaimer: my primary machine is a laptop, and it screams! I've got nothing against laptops! I just figured I'd lend my $0.02 as to why your laptop may be under-performing.)

 

[TimOBrien]

10-12ms on my Gateway XP laptop (with a Motu828mkII daisy-chained to a Glyph firewire drive).

Maybe you're not doing something right OR maybe there is something else causing a problem with throughput.

Are you using a built-in firewire buss on the laptop or a expander card (PCMCIA or such)???
Texas Instruments and Lucent firewire chips are just about mandatory.

Something just doesn't sound right....

 

[Whoopysnorp]

Bah, when I said ms, I meant samples, so 96 samples (~3-4 ms) on the desktop versus (as of my tests just now) 512 samples (~14-15 ms I think) on the laptop.

The Firewire on the laptop is built in; not sure what chipset it uses.

 

[Almy]

You can use the device manager to view what chipset your firewire is. But also look to see what other chipsets are in there. Unfortunately it's not just the firewire chipset that matters but others as well. One annoying thing you can do is disable other drives that aren't being used, including usb ports, to free up some of the problems. A lot of times the chipsets that 'manage' chipsets are cheaper and tend to be a roadblock. And some times disabling other devices they are managing can help.

 

[Whoopysnorp]

According to the vendor string it's a Ricoh chipset.