Re: OT: Power PC Laptop

[Rainer Straschill <moinsound@googlemail.com>]

Ricky Graham schrieb:
> I'm considering a power pc laptop (i7 Quad core 8GB). I'm looking at 
> the HP DV7t quadcore series. Does anyone have any knowledge of any HP 
> as a live performance machine?
Guess you're referring to the (Clarkfield) 720QM - which by its 
standalone price in the "processor power per money" is second only to 
the i5-520M, however even beats it in the available notebook systems 
(the performance increase by roughly 45% comes with a price increase in 
the 20% range).

The multicore vs. single core argumentation, as someone else already 
mentioned, is not as simple as suggested I'm afraid; there's a lot of 
things to factor in - apart from the softsynths and effects he mentions, 
also the VST host and the operating system, together with the specific 
kind of processor you're using.

 From a purely theoretical approach, for Windows users the best way to 
go is Windows 7. The reason: Windows 7 is the first (Windows?) OS to 
efficiently make use of the (i7) hyperthreading architecture - with XP 
and Vista, you might end up with not-multicore-optimized applications 
possibly running slower on a i7 architecture than on a i5 (or older) 
one. This however has been addressed in Windows 7.

Another important factor is the VST host: even if the individual plugins 
do not make use of multicore architecture, it is often sufficient if the 
host does: say you're running two softsynths and four effects, then the 
host can easily distribute those evenly among the cores if it has that 
feature.

Finally, the i7 architecture allows to boost cores specifically if 
others are unused: taking again the Clarksfield example of the 720QM, if 
you're only running two cores, you get a 798MHz boost on those - and if 
you assign your (not-multicore-enabled) application to one core and the 
sound driver to another one, you can redline the application core and 
still run extremely low latencies...

This is, basically, all a lengthy email to tell you that I don't have 
any experiences with the dv7 family (or HP notebooks in general). One 
thing to look for for audio hardware (just mentioning that in case 
you're not aware of that) is a characteristic called "DPC latency". 
Basically, it means how long it takes for some procedure calls to be 
processed, and for proper audio stuff, this should be constantly below 1ms.
Alas, only a few sites have started to test for that (e.g. 
notebookcheck.de - German), and typically the manufactures don't. But if 
you have the chance to have a look at the dv7 in a shop, be sure to run 
the following program:
http://www.thesycon.de/deu/latency_check.shtml

And btw, by just looking through some forums, I saw the following 
recommendation:
http://www.adkproaudio.com/laptop2.cfm

Anyone got experience with those?

          Rainer



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