Am I making a motherboard mistake?
May 29, 2006 9:23 PM   Subscribe

I'm going to swap the motherboard and CPU on my computer, please help me not screw it up!

Due to persistent overheating of the CPU in my 4-year-old system (P4/2.0 on an Abit IT7), and due to the fact that it's worse in the summer and it's very, very hot today, I am planning to replace them with a new motherboard and a reasonable Athlon 64. I used to know about hardware, but in the last 4-6 years I haven't cared, and now I'm pretty ignorant.

But I would like to make this motherboard (possibly with a later CPU upgrade) work for 3 or 4 more years, so I don't want to mess it up. An Athlon 64 3000+ seems like a fine choice for me, although in a year or two I might buy a faster one (possibly dual core) when they're cheaper (I don't have a ton to spend now). I will be transferring my three PATA hard drives to the new system, and my cheap AGP video card (The video card I'm trying not to re-buy is only a $40 card (bought solely for the DVI port), but $40 is $40.).

My application use is normal business desktop stuff, with some occasional photo processing and music tracker stuff (FLStudio) thrown in, but what I'm planning for is tabbed web browsing with background stuff. A decent number of apps running at once, most of them mostly idle. I use Windows XP Pro and Debian.

I spent the last four hours or so trying to figure all of this out, and I got most of it, but I have a big question left:

Am I shooting myself in the foot as far as the next few years go by choosing a (presumably older) motherboard with AGP support? It looks like my northbridge choices are nForce3, Uli M1689 and VIA K8?800. Is any of these better than the others? Is it worth re-buying the video card to get a newer chipset? Will these work well with the kind of dual core CPUs that are out now?

Oh, also I can verify that the overheating problem is not fixable. This problem appeared over two years ago, I spent a long time trying to fix it, and I have been enduring not letting my cpu load stay over 75% since then - it's time for a change!
posted by pinespree to Computers & Internet (17 answers total)
Oh, also I can verify that the overheating problem is not fixable.


Judging by your system requirements, it sounds like you probably don't need to upgrade right now if you can find a way to fix this overheating problem.

Just replace whatever is broken, I got a new fan that just bolted right onto my heatsink for NZ$7 that is not only quieter, but shaved several degrees off my average temp. You didn't say what you'd done to verify the cause of your over heating problem, but for all I know you just need to smooth out (or gently wipe off and replace) the thermal compound between the heatsink & CPU.

If the problem is the motherboard, just get a replacement for that. I got a replacement ASUS mobo (A7S8X) recently (2 of the old motherboard's DDR slots had failed) that kicks ass and cost little (about NZ$90), and of course all my old stuff just slotted right in.

You don't need a new CPU & MOBO if you're just running normal apps.

I've heard good things about nForce from friends, but never had a mobo with nForce myself.
posted by The Monkey at 9:50 PM on May 29, 2006

The problem you're likely to face is AMD's fiddling around with sockets: meaning that if you want to upgrade the CPU in a couple of years' time, you may need to swap out the motherboard as well. At which point AGP will be very much legacy. But even modern motherboards are likely to be caught up in that transition.

Chances are that you won't feel the need to upgrade the CPU before the next major swap-out, so I wouldn't worry too much. PCIe based motherboards definitely offer a smoother upgrade path these days, but that's aimed at people who are inveterate tinkerers. If you're not a gamer, and happy with your AGP card, there's no reason not to take the price premium of a slightly older motherboard.

Alternatively, you could always go for a socket 939 w/ onboard DVI such as the Asus A8N-VM CSM, which has four SATA ports and x16 and x1 PCIe slots, etc.

Either way, you ought to factor a new PSU into your budget.
posted by holgate at 9:52 PM on May 29, 2006

Socket 939 is pretty much at the end of its life. AMD has just released the AM2 line to replace it. They will stop manufacturing socket 939 processors at, I belive, the end of this year. That means that in a year or so when you're looking to buy a faster chip to stick in your motherboard, you'll be buying from a dwindling supply, which doesn't exactly do wonders for the price performance ration (check the prices on faster Socket A chips for an example). The story for socket 754 is similar.

That doesn't mean that you shouldn't buy a 754 or 939 socket now, but do it knowing that your upgrade opportunities in a year or more aren't going to be great.

As for your video choice, AGP is also dying, and it may be that you don't have very good options if you want to buy a new card in a year to get the most from windows Vista. PCIe will give you more options for upgrades in the coming years. For what you're running now though, AGP could suit you fine for a long while.

One option for you to consider is getting a board with integrated video. Both NVidia and ATI have decent solutions that should work fine for what you are doing now, plus, they come with a slot that you can use to upgrade. One thing I'm not sure about is the linux driver support for either solution.

I've got a Biostar 6100-M9 board that was cheap, has integrated video and supports a dual core socket 939 CPU nicely. I think I paid $60. I'm pretty sure you've got to go up another $10-15 to get something with DVI out.

If you want a lot of programs open at once, get 2GB of memory.
posted by Good Brain at 9:54 PM on May 29, 2006

Response by poster: The Monkey, the problem is with the CPU, and I could easily fix it by replacing the CPU, but rather than buying another P4 2.0 for $60, I thought I would set myself up for a few more years by upgrading a touch. My budget isn't unlimited, but it's not $0 either. I have tried a different heat sink, replacing the transfer compound, same cpu in someone else's mobo, etc.

holgate (and Good Brain), I had considered a 6150-based solution, but I was wondering about putting a Micro ATX board in my full-sized case. Is that a bad idea? If not, I like your suggestion. Do you suggest a new PSU because my old one is probably almost worn out, or probably not powerful enough? My memory is vague, but I think I bought one with more power than I needed four years ago.

Actually, learning that AMD will be quickly mothballing the 939 dies was very useful - I hadn't found that out, and it might make me actually buy a new P4 and wait for an AM2 cpu/mb. (or endure a few more months of overheating)
posted by pinespree at 10:08 PM on May 29, 2006

Best answer: I would like to make this motherboard (possibly with a later CPU upgrade) work for 3 or 4 more years

I won't try to address your overheating problems - increasing air flow, cleaning (dusting) your fans and boards, etc, etc, may make this problem go away.

Anyway, I was upgrading a while back and decided that my new mother board would need to be useful for 3 or so years. I went with ASRock's 939Dual-SATA2 mobo.

Sure 939 is being phased out - but the mobo uses a daughter card that will support newer CPUs. (a daughter card may cause some to roll their eyes - but if long term usability and upgradability are your goal then this is a nice if not optimal feature.) Furthermore the dual core 939 chips that are out there are more than you'll need for several years to come. The board has nice features like SATA RAID 0 & 1 support, an SATA-II port and of course PCIe and AGP.
posted by wfrgms at 10:49 PM on May 29, 2006

Best answer: There is at least one Socket 939 board with both AGP and PCI-E 16x slots - Asrock 939Dual-SATA2. It will be about the same price as the Asus A8N-VM CSM mentioned above though (~$100), so it probably isn't worth bothering with.

You might consider waiting for an AM2 board with onboard DVI and PCI-E 16x.. A board like that will probably be about $100 too, but the CPUs might be pretty pricey initially.. Then you get into that whole thing where you never buy because you are always waiting for the next big thing to come out first. Not a bad way to save money, but..
posted by Chuckles at 10:55 PM on May 29, 2006

Damn you wfrgms, for getting to it first..

but the mobo uses a daughter card that will support newer CPUs. (a daughter card may cause some to roll their eyes - but if long term usability and upgradability are your goal then this is a nice if not optimal feature.)

I wasn't even thinking about that.. The daughter board may be a little expensive and/or hard to find though.
posted by Chuckles at 10:59 PM on May 29, 2006

Best answer: If your case accommodates MicroATX, there shouldn't be a problem, as long as you get a well laid-out motherboard. And if your PSU is 350W, then you whould be okay: the specs for this Econobox look pretty decent to me.

But as others have said, now's not an ideal time to buy for a 3/4-year upgrade strategy based around AMD. There's always the possibility that, as AM2 rolls out, the FX-60 will become a bargain, but that's a gamble.
posted by holgate at 11:00 PM on May 29, 2006

Response by poster: Thanks for your help everyone - that turned out to be an easy issue to settle with your help. I will either go with the 939Dual-SATA2 and roll the dice on being able to get a faster processor later or (much more likely) wait six months and see what rolls out with AM2.
posted by pinespree at 11:05 PM on May 29, 2006

I was in the same boat a few months ago, the difference is that I absolutely needed the fastest system I could lay my hands on with dual-core, so I opted for the Opteron (ba-dum-bum). Socket 939/40 is basically at the end of its product lifecycle, but this isn't necessarily a bad thing for you, the consumer, as you can get some blazingly fast processors for dirt cheap as everyone plays the waiting game with the AM2.

That said, I also decided to upgrade everything else and get with the times, because most of my system's components were showing their age. All that stuff adds up. If you can afford to wait, I'd suggest the following:
  1. Get the absolutely coolest fan you can on that chip. You mention that you "tried a different heat sink" -- that's not sufficient. You need to get a new fan+HS, and use Arctic Silver for the thermal paste. I'd recommend the Thermalright XP-90C (Copper) with a good fan. That should bring your temps down to the 50's (C). A proper HS+fan will run you about $75. Don't be a cheapskate when it comes to your processor's cooling.
  2. The HS on your chipset fan is probably fine.
  3. Get the best power supply you can afford. OCZ, SeaSonic, or (if you can swallow the pill), the creme-de-la-creme, PC Power and Cooling. This is an area where it might behoove you to think ahead: many manufacturers provide 20+4 connectors for future compabiliity.
I personally found the Opteron 1-series to be an incredible performance/cost pricepoint, and if/when the time comes to upgrade, I can easily add another core(*2) to the system.
posted by Civil_Disobedient at 11:15 PM on May 29, 2006

Response by poster: When I said tried a new heatsink, I meant a new, very high quality heat sink and fan. I knew that I wouldn't be able to convince anyone that I had actually made an effort to fix the overheating problem, but I have. :) (It did not bring my temps down the 50s, nor the 60s, nor the low 70s - 100% load for 10 minutes still runs me right up to 75, at which point I stop doing whatever caused the load because the motherboard alarm goes off and the CPU throttles to 50%)

I will take your PS advice into consideration. I am thinking now that I will endure the overheating for the next few months and either take advantage of end-of-lifecycle savings on a 939, or get into an AM2 (I'll also set aside a few hundred more dollars, so things like my $40 video card and a new PS won't be an issue).
posted by pinespree at 11:37 PM on May 29, 2006

Best answer: Does the heatsink itself get finger-blisteringly ouch ouch ouch owie owie hot hot hot! hot when the BIOS reports 75° CPU temperature? If not, you may not be mounting the heatsink to the CPU the right way, and your overheating problems may well persist after your expensive upgrade. In fact it should be painful to leave your finger on the heatsink if the CPU temperature is above 50°.

To be effective, a heatsink needs intimate thermal coupling with the CPU. If it doesn't get it, the heatsink will stay relatively cool while the CPU gets hot. Intimate coupling means the thinnest possible layer of thermal grease. Ideally, both mating surfaces should be mirror-flat and there should be no paste at all in the joint except what's required to fill micro-voids; in practice, this is not achievable but must be given the old college try.

I've seen CPU's installed by supposedly reputable system assemblers overheat badly because of excess thermal paste sloppily applied. The worst one had a hard white crust almost a millimetre thick that looked like a precut square of double-sided sticky tape.

Ineffective and/or uneven cooling can also result if somebody has replaced a heatsink on an existing CPU, and failed to remove every skerrick of old thermal paste before mounting the new sink. You don't want lumps of old paste forming support pillars for your fine new heatsink; a 0.25mm gap filled with expensive Arctic Silver paste will perform worse than a 0.01mm gap filled with margarine.

Before the heatsink goes on the CPU, absolutely every scrap of old gunk must be removed from both surfaces. The top of the CPU should be mirror bright and unblemished. The bottom of the heatsink, ideally likewise; the brushed-aluminium look is probably OK but if you can polish it up a bit without destroying its flatness, so much the better.

Apply the absolute minimum amount of thermal grease - certainly no more volume than a match-head - to the centre of the CPU, put the heatsink on top, then slide the heatsink back and forth and around and around to spread out the goo. Now take the heatsink off again and examine the top of the CPU. You should have a dead-even layer of grease, thin enough to be virtually transparent, and most of the blob you applied should have come off the edges.

Wipe it all spotlessly clean and do it again, this time with even less grease.

Once you're convinced that you can do a good job with the grease, clip the heatsink down at the end of the smearing process instead of taking it off. Don't take apart a greased joint and put it back together; bubbles are as bad as crumbs of old gunk and, like those crumbs, can cause local hotspots.
posted by flabdablet at 1:49 AM on May 30, 2006

Oh, yeah. To get crufty old gunk off the top of a CPU, attack it with an oil-soaked cotton bud and lots of patience. You don't want to scratch that thing up.
posted by flabdablet at 1:51 AM on May 30, 2006

Best answer: Does the heatsink itself get finger-blisteringly ouch ouch ouch owie owie hot hot hot! hot when the BIOS reports 75° CPU temperature?

That's the critical test. Stop the fan by unplugging it, put your finger on the heat sink, and turn the computer on. The heat sink should quickly feel warm to the touch, and may become hot to the touch. A safer way is to use a temperature probe.

Heat sinks sink heat -- that is, they are large masses of thermally conductive metal. Aluminum is the most common choice, copper is more conductive, but more expensive. They're finned to increase the surface area, so they radiate and convect heat away quickly.

However, the interface is critical -- if the heat sink isn't in contact with whatever is hot, the air gap reduces the flow of heat. Air that isn't moving is one of the more effective insulators known. This, by the way, is how down jackets work -- the down traps and holds air that doesn't move.

In an ideal world, you'd machine, polish, and lap the contact surface to truly amazing flatness -- so that the surfaces were so close together that the Casimir Effect becomes noticible. However, that's not going to happen.

So, we get them reasonably flat, and use a paste or conductive pad to get rid of the air gap. The rule, however, is simple.

Thermal greases aren't great conductors of heat. They're vastly better than air, but they're not as good as metal. So, use the least possible.

My procedure.

1) Clean both surfaces with high grade alcohol.

2) If the surfaces of the heat sink is really beat up, sand it down, to at least 2000 grit smoothness. If you don't know how to do this, buy a new heat sink. Ideally, you'd get a nice mirror polish. CRITICAL. It must stay flat.

3) Put some heat sink compound on a piece of paper.

4) Take a cotton swap, dip that into the compound, wipe it onto the top of the CPU, and spread it around a bit. Yes, we're using very little compound.

5) Install heat sink, but don't install fan. Turn on power. If the heat sink doesn't warm in a couple of seconds, turn off power, add a little more compound, repeat.

I keep seeing these tube of compound saying they have enough for 2-3 CPUs. That's inane. With decent CPU and heat sink surfaces, there is enough in one small tube for 20-30 CPUS, and a small stack of TO-220 transistor heat sinks as well.

What these CPUs really need is a heatsink with threaded holes, so we could get the force we need to get a good contact between the heat sink and the CPU.
posted by eriko at 5:00 AM on May 30, 2006

Response by poster: Unfortunately, yes, the heatsink is blisteringly hot. The fact that I could barely stand to touch it led me to believe that it was working ok (and that there was just plain too much heat there), but you've all been great with your suggestions, so I think I'll try again and see if I can get a few more watts of transfer out of it. Thanks!
posted by pinespree at 8:27 AM on May 30, 2006

Here's a step-by-step tutorial on how to properly clean off your heatsink and chip (lapping) for optimal thermal transfer.
posted by Civil_Disobedient at 9:23 PM on May 30, 2006

What does the BIOS report for CPU voltage? If it's too high, that will cook things right up.
posted by flabdablet at 6:57 AM on June 2, 2006

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