[mythtv-users] What hardware do I need to be able to dual record using Comcast cable?

Janne Grunau janne-mythtv at grunau.be
Fri Oct 17 16:17:43 UTC 2008


On Friday 17 October 2008 16:25:36 Robin Hill wrote:
> On Fri Oct 17, 2008 at 08:04:56AM -0600, Greg Woods wrote:
> > I have not tried running an OS written for a 32-bit chip on a
> > 64-bit chip, but even if this worked, it seems to me that I would
> > be sacrificing some of the chip's performance to do this, and since
> > the whole idea of moving to a 64-bit chip is to get better
> > performance, this strikes me as throwing the baby out with the bath
> > water. Sounds like I would have to make a tradeoff between
> > stability and performance, and I'd really rather not have that on
> > my Myth system. Thus my desire to avoid going to a 64-bit chip.

I haven't seen any 64 bit related stability problems and amd64 is around 
long and common enough so that most issue should be resolved by now.

> There's no inherent performance improvements with a 64-bit chip over
> a 32-bit chip.  If the application deals with 64-bit integers anyway
> (very rare for general purpose apps) then you'll get a boost. 
> There's also specific architectural improvements which were brought
> in with the AMD 64-bit chips (extra registers) but this is
> technically independent of the 64-bit nature of the chip.

They are only available in 64bit mode, so it is related.

> The main reason for switching to 64-bit systems is the ability to
> address larger amounts of memory (without needing to do any page
> switching) - 4G is pretty common nowadays and 32-bit systems
> generally fail to make use of all of that, let alone any extra.

That's the main reason for servers or scientific applications dealing 
with large amounts of data.

> In short, I wouldn't worry about running a 32-bit OS on a 64-bit chip
> - you're not likely to notice any performance difference.

I disagree. Video decoding is approx 15% faster in 64bit mode. Generally 
this is not a noticeable difference, especially since video playback 
usually only needs real time. OTOH for h.264 HDTV it could be the 
difference that make a video watchable.

Janne


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