I.D. a processor to start a Car Computer System.

Jistari · 12-10-2007, 05:04 AM

Alrighty then, some quantitative opinions needed.

I'm pretty square on building a desktop, and although my experience is a little dated, I can find my way through the
advantages/differences among various technical specs (i.e. the difference between a P4 class machine and a Core 2
Duo, or the impact of a faster front side bus speed) for a desktop but I find myself out of my depth when trying to
evaluate the relative processing power of the types of processors available for mobile computing.

What I'd like to end up with is the Xenarc MDT X7000 head unit (so that will take care of AM/FM CD DVD and the XM
music feed through RCA jacks, all right in the head) and a car computer to handle Internet Browsing, Blue Tooth Phone
access, NAV, a front end and the XM station feed so I can control it from the head.

I would think that a straight Pentium M class processor with a seperate video card (64 or hopefully 128 meg) and a meg of memory running Win XP
would handle the load well enough, but do get the feeling that offloading the graphics proscessing to a GPU may
increase the power and cooling requirement past the point of easey trouble free operation in a mobile environment.

The car (a 2001 Corvette is blessed with a beefy alternator/battery/electrical system) also has a well founded
reputation as a power hungry beast (theres nine computers in there from GM, this is not a car you let sit all winter
and expect the battery to be ok in the spring, I keep it on a battery tender), so I'm endeavouring to build this
system as properly as I can to maintain its usefullness with as little impact to the rest of the systems in the car
as possible.

I feel that once I can ID the proper proscessor, I can probably stumble through selecting the rest of the components
based on past experience, reading here, and the help of you fine people :-) .

My problem :

I've been reading for about a week now, but there is a lotta suff out there. You can redily find the specs on a
processor or a motherboard, but it is often difficult to compare one unit to another when you havent used either.
They all say "blah. . .blah . .powerfull graphics processing engine . . .able to handle the most demanding
applications . . ." so that really leaves you right where you started (they all cant be right :-) ).

I dont need the fastest system out there. Im not going to be playing games on it. It just needs to be able to run the
front end, put the xm data up on the head, play digital music off the hard drive and browse the internet at wi-fi
hotspots (that stuff should be handled by pretty much any of them (correct me if Im wrong) and run a software based
Nav off the Hard Drive <== that would be the most demanding application I would guess.
It will be in a good car computer type case, with a good auto grade power controller.

What I need :

Can someone answer a few qualitative/quantitative questions for me ?

==>Am I correct in thinking that a P4 or Pm processor would be up to that task?

==>How powerful (in relation to current desktop processors) are the mobile like the Via C7's (or even E15000).

==>Is it feasable to be looking at a desktop CPU with a seperate video card, or can the mobile processors handle
running the system and also doing the video?

==>Just to give me something to work with, can someone please ID 1) The most powerful mobile processor out there
right now and 2) the least powerful one that would be likely to handle the load I described above. If I can establish
a range, I can move forward on selecting the other components. As I mentioned, if it were a desktop Id be ok. I
would know that the bottom end would be a P4 or Pm and the top would be a Quad Core, but I would also know that I
dont need the Quad :-) (see my problem :-) ).

I know better than to ask which front end or Nav package works best :-) but . . .if you want to chime in, I will
gladly add your insight to those choices when I get there, after the hardware stuff gets sorted out.

Thank you in advance for any assistance you may provide.

2k1Toaster · 12-10-2007, 05:27 AM

Yes a P4 is plenty. Most people use Via systems which use a C3 or C7 processor. A Taiwanese ripoff of an early Intel Celeron chip. A 1Ghz to 1.5Ghz C3/C7 is common and powerful enough for audio, video, gps, everything. Bluetooth actually is incredibly slow though from what I have heard, and I think it is just the crappy drivers available. But a 1Ghz C3 (m10000 motherboard with embedded CPU) draws about 25W of power at maximum for the CPU/Mobo and is the equivalent processing power of a Pentium 3 700Mhz-800Mhz.

A Pentium 4 is a power hungry SOB. These (especially the Prescotts) are not meant for the mobile environment. The Pentium 4M is much much better at power. I use a 2.2Ghz P4M and it is more than ever needed. I do however run AutoCAD 2007, Adobe Photoshop CS2 and other demanding apps in my car as I sometimes need some thing to render on the drive to school. Think procrastination of homework.

A 1.5Ghz P4M should be more than enough. The Core2Duo's are more than you need now or ever. And I can safely say that, because no matter how hungry the OS becomes, or anything, music is music. You cannot cram more data into a song then there already is. Lossless audio exists, and there isnt anything more lossless, than lossless. As for video, the compression will get better, and maybe a 1080i full feature film can get down to a few megabytes, but do you need 1080i on a 7" screen with a maximum resolution of 800x600 (Actually a bit different since it isnt 4:3)? The benefit is the power draw.

So get what you can afford, but if you look at truckinmp3's setup, he uses a 400a celeron as his computer and it runs fine for audio.

Mobile processors are beefy enough already to run onboard audio and video. No 3D renderings here. Even milkdrop 3d visualizations run fine on onboard graphics.

Also think that the power limitation is not your vette's alternator. It is the maximum output of a DC-DC power supply. The more the output, the higher the price. Get too much power and you are limited to running an inverter. Inverts introduce noise and unneccesary evils.

Also think vibrations in the car. Same reason you dont want a liquid cooled rig in the car, you dont want another little port like PCI or AGP with those little pins moving around. You can glue it in, but unless you do, it will fallout, and it wont be fun when it does. And if you want a cool case (non-custom) you wont be able to squeeze an external card anyways.

1) The most powerful right now that I would even think to use in the car is the C2D T7600. Next spring there should be the mobile Quad Cores, but again... why?

2) I think a M10k is your minimum spec. A C7 1.5ghz should be plenty with room. And even in a desktop, since when is a P4 the bottom line? I have an AT that still works with its 5.25" and 8" disk drives.

Many P3 systems doing things like servers and HTPC's. A P4 is still top of the line for anything but gaming... How resource intensive is office?! Comeon!

<opinion>And as far as frontends, RoadRunner is the best free windows based frontend period. </opinion> There are others like StreetDeck and Centrafuse which come with nav software, but they cost money obviously.

Jistari · 12-10-2007, 06:48 AM

Thank you

That is exactly what I was looking for.

I'll wait for other input but am leaning towards a P4m (probably along the lines of your set-up) I know its overkill for the normal car tasks but its always good to have a little room at the top end. I may make some demo's (just eye candy to run on the screen at car shows) that could use good graphics performance.

Appreciate your time.

Jistari · 12-11-2007, 12:13 AM

Any mother boards that I should avaoid due to "flooky" graphic drivers? Or any that are particularly good? (graphic driver wise that is)