Re: [Discuss-gnuradio] Good laptop for GR/USRP

[Marcus Leech]

Bahn William L Civ USAFA/DFCS wrote:
> We will (hopefully) be purchasing some new laptops specifically for use
> with the USRP and wanted to get any recommendations on particularly good
> machines to purchase or, failing that, what specs to focus on.
>
> This is my present thinking - please correct any misconceptions I have:
>
> 1) Dual core is probably a very good way to go, especially since our
> applications are going to involve a signal processing thread and a
> control thread.
>   
I just started using a Pentium D 940-based dual-core system for my radio 
astronomy work.
 I'm happy with it, but it's not a laptop.   Eventually, Gnu Radio will 
support multi-threading
 for processing blocks that are particularly expensive, I think, which 
will be much more useful
 on multi-core CPUs.  Currently I think only the signal processing and 
Gui chains are in different
 threads, but that's a start...


>  
> 2) We want to get as much processor speed as we can get.
>   
Laptops usually lag desktops in raw clock rate.  You want something with 
a manly cache.
 My Celeron D machine at 2.95Ghz was unable to keep up with 8Mhz radio 
astronomy
 processing, but my dual-core Pentium D 940 with 2M cache per core 
machine is easily able to
 keep up with 8Mhz radio astronomy work without any USRP overruns.
> 3) Memory probably isn't a huge concern. We will probably be getting 1GB
> of ram.
>   
Double that and you'll likely be happier.  The virtual size of Gnu Radio 
applications is
 quite large, and the working set size is also surprising.
> 4) In order to capture long data sequences, it would be nice to have a
> speedy throughput to the hard drive. What is a good solution here - as
> in what is a reasonable set up that is considerably faster than the
> run-of-the-mill hard drive and controller? (When all is said and done,
> we'll live with what we get, this isn't super important to us).
>   
Disks I can't comment on.  Laptop drives tend to be slower than their 
desktop
 buddies.
> 5) What processors should I consider and/or avoid? My understanding is
> that GR leverages the advanced floating point capabilities of modern
> processors, but I have no idea which ones are particularly good or
> particularly bad.
>   
Avoid small-cache processors.  But if you're going dual-core, you'll be 
getting something
 with much more cache than the 256K in the Celeron D.
> 6) How much does the video card affect things? Does it affect non-GUI
> applications very much (as in, does GR use the processing capabilities
> of today's video cards in any significant way for non-video
> processing?).
>
> Thanks a lot!
>   
Gnu Radio doesn't (yet) leverage the computing capabilities of the 
graphics card.  Garden-variety
 graphics cards are just fine--that's what I use for radio astronomy stuff.