Dell Dimension 8400 CPU upgrade

AboveDaClouds

The Dimension 8400 only supports 4gb of RAM, changing the processor and OS will not change this, the amount of ram a system can use is determined by the capabilities of the motherboard, basically the BIOS and memory controller.

Bev.

AboveDaClouds,

No - there was no fan included with the CPU, only the chip itself.   A Prescott Pentium 4 P4 670 3.8 Ghz SL8PY 2M Cache 800 Mhz FSB Hyper Thread. The chip did work but when I loaded the box the chip obviously got hotter and the fan got faster and noisier and stressed me out !! - Tried it for a few days but couldn't take the noise in my very quiet office.

You may not suffer from the same problem - Best of luck with your trial. Post your results and let us all know.

Ron.

Ah I see thank you.  Would the change mean that the full four gigs is seen and used by the system at least?   I thought that part was an XP limitation--thus my confusion.  It's fine as it runs pretty well with the recognized 3.25--it's not slow or anything, but I'd love to have the full four of course :).

AboveDaClouds,

It is my understanding that the 4Gb limit on the Dimension 8400 is a limitation on the chipset / motherboard and also that this 4Gb limit is a limit for all the memory addressed (including video card and other stuff), not just the ram. So even using a 64-bit OS will not enable you to use all 4Gb ram. (I am 99% certain I even read a thread on here a while ago where someone asked why when they upgraded to a 64-bit OS on the 8400 that the full 4Gb ram wasn't visible and this was the verified answer given).

Munro284:  gotcha I was following a different seller from the looks of it. Sorry to hear about your trouble with it, I sure am hoping my experience is closer to 2-J's.

2-J :     Yes I saw that thread recently...something about that last gig being reserved for hardware use or something. I think they mentioned there that it may bump slightly up from 3.35 to 3.5 or 3.6 though.

Now as far as  graphics cards  I have had a couple video cards with 1 gig of ram in addition to my four.  Those were recognized and used during differently-- I'm fairly certain {and gratefully so} that that limit does not include the graphics card ram.

I wasn't planning on upgrading the OS immediately mainly because I'd have to do a clean install and I understood someone to say that I the 670 will still recognize my 32-bit OS?  I sure hope so  I dread reinstalling all of my programs again.  I guess that's being lazy but once I see how the 670/or 672 is running I may change my mind.

Did you use your stock heat sink and fan?

I see opinion is divided about the noise with some attempting cooler/heatsink upgrades and some seemingly doing just fine without the upgrades.  We 8400 owners seem to be cornered with the tiny space around the CPU.  At any rate I'm crossing my fingers and taking the plunge.  I'll update with results and specs when I can.

You've all been very helpful, thanks.

I didn't do a reinstall of my OS or programs when I put in the 670, I don't think it's necessary.

About my heat sink and fan, I had a problem with them *before* I installed the 670. In an issue that I have read about on more than one forum, it seems that the heat sinks in some 8400s were faulty (iirc)... anyway I used to have incredible fan noise (this was even before I put in the 670, as I say) so I replaced both the heatsink and fan / shroud. But with official 8400 parts. And since then, for years now, I've had no problems with excessive fan noise.

So to answer your question, I am using a stock / official Dell Dimension 8400 shroud, fan and heat sink and didn't need to change that with using a 670 processor.

I too have a 1Gb graphics card in my 8400 and you're right when you say that the visible system memory's relationship to the graphics card memory isn't completely straightforward. At the moment, with the 1Gb graphics card, I have 3Gb ram visible to the OS. But I have used 128MB and 512MB cards previously and it wasn't the case that the visible OS memory went down by 512MB when I upgraded from a 512MB card to a 1Gb card. I read somewhere that it's related to how the graphics card drivers allocate / map memory, rather than being simply a matter of how much ram is physically on the card.

2-J:  Thanks for the info. To date I've never had a problem with the heatsink and fan, I just heard that these processors may need more so I was a tad worried..  It seems like you're doing fine with the stock one though so that's what I'll hope for.  I did figure an upgrade couldn't hurt but the space inside is so tight trying to upgrade seems a real challenge.

When you say you used a stock part did you mean a dell recommended upgrade part or just the replacement for the defective heatsink?

I saw something about putting in a Zalman on one of the threads but got lost somewhere in the middle of the discussion because links didn't work.  It's good to come here though because I see there's really something about the 8400 that keeps the owners here hanging on to them. For me, my computer performs right along with the newer models with no real noticeable speed differences imho.

I do a bit of gaming too--and for the small amount that I find time to do this old 8400 runs just fine--with the power and video card upgrades that is. I can only guess that when I upgrade the CPU that will put the icing on the cake for me.

AboveDaClouds,

I replaced both the heatsink and the fan and shroud, but with official / authentic parts, maybe I'm not using the right terminology here but what I mean to say is I am using the same kind of parts as originally shipped in 8400s, not a zalman fan or whatever. And the reason I replaced my original fan, heatsink, shroud was because I fan problems *before* I even upgraded the CPU. As I said I have read that some heatsinks originally used in the 8400s were faulty.

I haven't found it necessary to use a different kind of fan or heatsink and the 670 has been in my 8400 for years. No noticeable increase in fan noise.

Like you I'm very happy with my 8400, I have upgraded it to 4Gb ram, 500W PSU, 1Gb graphics card, 670 chip. But I'm coming up to 9 years of owning it so the cost per year has not been that much. I still game on it too. I'll be upgrading the OS to Windows 8 when XP support ends.

Foxconn made a special heatsink-with-fan for certain Dell 'clamshell' models and I think it fits the 8400.

I have seen these on eBay.

what advantages in speed have you got considering it's a old machine is it worth spending money on it ?

what advantages in speed have you got considering it's a old machine is it worth spending money on it ?

I agree, especially as the Dimension 8400 only support single core P4 processors and nothing that's dual core.

Bev.

You both make a fair point.   Dell gold support  took care of it for the bulk of it's life so there's been no pain of ownership of this computer for most of these years.  When that support ended a few years ago I began to slowly upgrade.

If you've kept it up like I have the $39 spent on a P4 672 is worth it.  Like I said it performs very well--more then satisfying my purposes and gives me great gaming when I want it.  I don't regret a few added sticks of ram,  a video card upgrade, or a more powerful PSU when I needed it, as it amounts to less then $200 in a slightly more than 9 year lifespan.  I couldn't replace this computer with one that runs as well for that amount if I paid it all at once right now.   A  few dollars and a little effort over the years is certainly worth that.

For business purposes it does fine although there are both dual and quad cores here to use.   I have a dual core laptop at home also as well as mini laptops, etc.  I still prefer My old 8400 :).

I am doing a few custom builds for my children {who want total gaming power} so that's where a fair amount of money will be spent.  Next to those this one will likely seem a snail but I'll probably join them for the fun and return to old faithful for my low key gaming and other needs. To each his own it what it amounts to guess.

I have seen many people overestimate the cost of upgrading Dell PCs particularly the 8400.

There is a 'buy it now' Pentium 4 670 on ebay now for 15 bucks. You can probably pick one up cheaper, by bidding in auctions. That will offer an appreciable difference to what AboveDaClouds currently has in his PC. I personally would not pay the extra money for a 672 unless you are confident you need and want hardware virtualization - other than that, the 670 offers identical performance.

Another thing people get wrong is the performance of these machines, thinking they offer worse performance than they actually do - probably because they have never tried to use one to run modern applications / games. I have put 300 hours into Elder Scrolls : Skryim on this machine, it runs fairly smoothly on high settings. Granted I have a 1Gb graphics card in my 8400 now and a 500W PSU, but the cost of ownership over almost 9 years has been low, in my opinion.

2-J:   You're spot on about the overestimation and about the performance of the 8400.  Even when I began upgrades in 2009 I was quoted all kinds of outrageous costs for just about everything I asked about.  Made it sound like I'd need anywhere from $800 to $2000 to do anything meaningful.  Of course it only took a little knowledge and a few clicks to find out that wasn't the case.  One thing this comp did for me for sure was teach me about where everything is inside and how to build my own.  (which is a lot easier when you lose all the Dell proprietary stuff like rigged power button etc., and just get your own case).

On performance, unless someone is running with a ssd installed I've seen no real difference in response times or satisfaction with either work applications or games between this "old" computer and newer models.  Then again I'm not comparing it to my "as shipped" dell 8400 but to and upgraded one. 650 psu, max ram, 1gig video card ram(256 bus) and more then 1tb of space.  So $15-$39 for a cpu uprade vs $1500 for a new one that may save me a few seconds? Nah I'm good for now :D.

If that 670 comes with free shipping I might consider it.  I did want the virtualization for windows 7 to be able to run xp mode but I've never even checked out xp mode on the windows 7 computers I have here so it may not be worth it.  Thanks for the tip--oh and it's she btw ;).

P.S. Oh wow Skyrim?  I never installed it on here--partly because of  the odd scoff (from gamers with newer models) at the poor graphics I'd have trying it on this one.  I don't have it on the newer ones I own because they are business-focused so I couldn't exactly compare. Can't wait to check that out now.  Another fine tip! Thank you.