Need opinion on main board

[Mikesz]

Ive decided to not go the M10000 route and use a micro-atx board. The parts I have so far are AMD XP 1600, 1gig PC133 ram (2x512), ATI rage fury pro, and an opus. I would like to upgrade to DDR later when I have money.

The board I found is the MSI KM2M Combo-L. You can view it here

http://www.newegg.com/app/ViewProduc...roperty&DEPA=1

http://www.msi.com.tw/program/produc...&MODEL=MS-6738

It has
6 usb 2.0 ports (4back 2 front)
2 SDRAM and 2 DDR slots up to 2gig (DDR or SDRAM not both)
onboard 10/100 ethernet
2 serial ports! (1 is intel spec Jcom2 though?)
4x agp
3 pci slots

The agp is only 4x, but so is the video card I want to use, it also has integrated video and audio, which may come in handy if I ever pull the board from the car.

If you guys know of any better board out there please let me know. I dont really mind if it dosent have sdram slots, thats really more of a convience thing. Im sure I could come up with $70 for DDR ram if I had to.

Thanks for reading this and for any opinions/information you may have.

mike

[Telek]

For starters, why do you need a 1.6GHz machine with 1GB ram **in your car**?

The Opus won't power all that. Incidentally the 1.6GHz (0.18u) takes 63W (~13A) of power max, and the 1.7GHz (0.13u) takes only 50W (~10A) instead. In either case, the max the opus can pump out is 12A which in both cases will be too little. (especially if you keep the rest of the system like you describe).

Don't forget, not only can these things get stolen, but then you have to worry about powering such a beast, which will be difficult with a DC-DC solution. You'll need to go KeyPower to get that much power out of a DC-DC, which adds $100 to your previous cost.

I'd seriously save your money and buy something a lot less powerful, unless you plan on ripping DVDs in your car in your spare time.

And really there is absolutely no reason to have 1GB of ram in your car, if anything it would be better to have less, not only because of taking less power but also if you ever want to use hibernate mode, it'll take 1/4 the time to read/write 256MB of ram to disk than it will take to write 1GB.

I would seriously reconsider putting that kind of power into your car, why not just get something cheaper and save your money? Unless you plan on hacking RSA in your car, even a 500 will run movies and mp3s no worse than a 1.6GHz machine can, but with a lot less cost and power requirements. DDR is completely unnecessary in your car.

[Mikesz]

What is the fastest system I can power with an opus? The ram is 2 512 sticks, so maybe ill only use 1. I already own the opus. The XP1600 is in my desktop computer, I was going to upgrade that. I will call opus monday to find out what they recommend.

As for the speed, I had a celeron 800 in a sv24. It was just a little slow for me. There were noticable slowdowns and skipped frames in divx.

mike

[Telek]

What type of DivX were you playing back?

IIRC, A Celery800 should be plenty for playing back DivX. I've played back divx on a PIII/500 without issue. I think that it must have been some other issue rather than processor power. What resolution DivX and what DivX version?

What happened to the SV24?

Intel chips generally take less power than AMD chips. Check out the processor power graphs for more information on processor power consumptions (damned excel save-to-web).

Don't forget, the motherboard uses a step-down voltage regulator to provide the power to the CPU, which is only about 85-90% efficient (i.e. add 15% to the wattage to get power drawn on the 5V rail). In the case of P4 systems they draw the power off of the 12V rail instead.

Additionally there are many other components that draw power from the 5V rail in your system, however I think that the wattages listed are absolute maximum power draws (i.e. I never see those actually on my system).

[Mikesz]

I downloaded the bundle from divx.com in december, so whatever they had available then. I was using an old WD 30gig 5400rpm drive that was on its way out, so maybe that was causing my divx problems. I have no idea the specs on the divx files or even how to check them. All movies that played slow on the fv24 played fine on my desktop XP 1600 machine with the rage fury pro thats in system 1 below.

The XP1600 is in my desktop, I was going to upgrade it and use the 1600 in the car. I read one of your other posts saying the 0.13u 1700 should run on an opus, so ill do that.

The fv24 died due to a bad power supply. The ram is still good but I have no way of testing the CPU. I was never really impressed with the fv24 due to problems with getting it to work correctly (drivers and such, mainly video drivers).

so far, these are the options I have come up with.

system constants
opus (own)
wd1200jb 120gb 7200rpm 8mb cache ($125)
usb sound ($80 i think)

system 1
ECS K7vmm mainboard ($50)
micro-atx
agp 4x
usb2.0
10/100 ethernet
512 pc133 (own)
ATI rage fury pro (own)
Athlon XP 1700 thoroughbred 0.13u ($65)

system 2

fv25 ($110)
integrated video
usb 1.1 (no 2.0)
pc133 512m (own)
celeron 800 if it works (own)
PIII 1g if /\ dosent work ($90)

The micro-atx will be much more upgradeable which I like. Its bigger but I have the room for it. The only reason I need usb2.0 is if I use it to communicate with a cdrom drive. I dont know what to do.

mike

[Telek]

what do you have (in total) in your desktop PC? maybe I can recommend something if I know everything that you have.

I said
Incidentally the 1.6GHz (0.18u) takes 63W (~13A) of power max, and the 1.7GHz (0.13u) takes only 50W (~10A) instead.

[edit: oops, foot in mouth time, I was looking at the specs for the 3.3V rail (max 10A) instead of the 5.0V rail (max 12A)].

The Opus won't be able to power either. It **might** be able to power a 1.7, but most likely when the processor maxxes out the system will reboot or lock up. The max the Opus can put out is 10A on the 5V rail, but don't forget that the processor power is created using a switching regulator as well, meaning that it's only 85% efficient, so add 17% onto the max power drain for your processor. And there is also other 5V accessories in your computer, so really the processor can tax max 70% of the max output of the PSU, meaning 7A.

HOWEVER -- The Sproggy 2.6 and 2.8 which are in use only have 5A on the 5V rail, which according to the PSU guide could only power like 10% of the CPUs out there, but apparently people are using it. Perhaps this is worthy of checking on, because the information that I am basing this reply off of could be incorrect.

[Mikesz]

The desktop PC is staying the desktop PC. I was planning on buying a new CPU for it, and using the 1600 thats in it now in the car. But you said the opus will not power the 1600 becouse its 0.18u and uses more power.

I was reffering to this thread about you saying the 0.13u xp1700 should be ok with the opus.

Anything more powerful than a 150w opus?

What I have for sure
2 sticks PC133 512 meg ram
1 stick pc2100 DDR 512 meg ram
Opus
intel CPU fan for celeron 800

what might work but not sure (going to try to find some way to test)

fv24
celeron 800

a bad power supply toasted the above combo. Overvolted one of the rails im sure. I dont know which is more likely to be bad, the board or cpu. I would guess that the step down regulators could have saved the CPU, but im not sure.

mike

[Telek]

My mistake, I was looking at the 3.3V rail in the specs (10A), the 5V rail is 12A, so it should just power an xp1700 (but it'd be close). You can push the limits of the PSU a little bit too.

I would guess that the step-down regulators to power the CPU(which by definition have to be variable-output) can most likely handle a wider range on the +5V rail, but it really depends what type of regulators they have to use. So your CPU is probably fine. What exactly happened to over-voltage one of the rails? Which rail did you overpower and by how much?

Because of that, even if it was the +5V rail that was overvolted, it's most likely to hurt something on the mobo rather than toast the CPU.

I would recommend sticking with the Celery 800 if you can, as I really don't think DivX should skip on that system. Stick with only 512MB ram, and that way the opus can power that system easily (25W required max). However it's your money, so feel free to do whatever you want But Yeah the 1600 is definitely out, the 1700 should *just* work provided that you don't try to run anything else off of the +5V rail. Incidentally if you DO need to run anything else off of the 5V rail, you can make a really simple +5V 5A regulator and either run it off of the 12V rail (there is 5A available on that rail, most of which you probably aren't using), and just run the +5V from the opus to the motherboard only, and use the +5V 5A from your add-on to power anything else requiring 5V. That would be a simple solution and would require very little extra parts (you can get the LM2678T-5.0 and inductors free from National/Renco, or use the MAX787 instead from Maxim, but they're slow to deliver whereas National is crazy fast).

Actually if you did that above method, then you might be able to power the XP-1600 off of the Opus just fine too, but what you'd have to do is find out the specific +5V wire that runs to the ATX connector that powers the CPU and leave that running to the Opus, and run all other +5V wires to your add-on circuit. You'd need to do this because there are other devices that use 5.0V off the motherboard, for example USB. The whole purpose (I think) of designing the ATX connector to have multiple inputs for the same voltage is that they're used independantly on the motherboard, so the PSU can have several isolated +5V rails that provide (for example) 5A each, without worrying about the problem when you join them together and have one rail that produces slightly more voltage than the other, causing a reverse voltage to run through the weaker regulator, possibly damaging it. In this case we can use this to our advantage, and you don't need to worry about how to control the extra +5V rail because you can run it off of the switched +12V, since you most likely won't use all of that power anyway.

[Mikesz]

Originally posted by Telek
The whole purpose (I think) of designing the ATX connector to have multiple inputs for the same voltage is that they're used independantly on the motherboard, so the PSU can have several isolated +5V rails that provide (for example) 5A each, without worrying about the problem when you join them together and have one rail that produces slightly more voltage than the other, causing a reverse voltage to run through the weaker regulator, possibly damaging it. In this case we can use this to our advantage, and you don't need to worry about how to control the extra +5V rail because you can run it off of the switched +12V, since you most likely won't use all of that power anyway.

but would this not cause voltage potential differences in the MB CPU somwhere that would cause current to flow where its not supposed to or cause problems with communication? You would think that engineers would anticipate things like this and design in ways where this would not be a problem, but im sure you know about engineers and supposed to, espiacially when every fraction of a penny counts in such a competative market

mike

[Mikesz]

I really did want to run the micro-atx amd xp system but the shuttle will be a lot less work. Especially since I already have a case built. I wasn’t really all that impressed with the shuttle because of drivers. The fv24 is no longer on their site, the fv25 is most likely soon to be out the door to. There goes support for the board, not to say I could get any know. Also if my celeron 800 is dead, ill have invested more money in the slower non-upgradeable shuttle combo than I would have on the faster AMD.

mike