Seems like hot air could easily circulate around in the case.

Making sure that intakes are only intakes and exhausts are only exhausts might help .

From what I can tell, I'm pretty certain the PSU fan is the only input, and the CPU fan is the only output based on an arrow on the PSU suggesting air flows through it into the case... I held my hand against both the exterior of the PSU and the interior fan, and while the fan was spinning, the airflow was definitely weak. Perhaps I'll ask a buddy to help me design some custom fan mounts or something, I think there might be an extra fan pin in there, might be able to stuff another fan for circulation perhaps. Thanks

Looks like some small (40mm?) fans before the PCI slots pushing rearwards and some more at the rear next to the CPU blower might help eject hot air.

The only intake being through a warm PSU isn’t going to be ideal though.

I'd try to just undervolt the CPU to have it run cooler in trade for a small performance hit (the CPU is 600 MHz over the recommended requirements for the game I want to run, so I'd be content losing 300-400 MHz), but Dell of course does not want people doing that, and I didn't see anything in the bios in this guy to help... I'm pretty sure the dips in FPS I'm experiencing are due to a little thermal throttling, so would swapping in a 3 GHz P4 in that case reduce that issue? Or is that just the nature of P4's in general? I know they ran hot, but I don't know if that's just because I have a higher clocked one...

Change thermal paste to PTM-7950. It's a "set and forget" phase changing material that resists pump out and is one of the best for heat transfer.

Normal thermal paste will pump out and leave very little on the surface in a few years.

RubDub2k wrote on 2025-02-22, 10:31:

I'd try to just undervolt the CPU to have it run cooler in trade for a small performance hit (the CPU is 600 MHz over the recommended requirements for the game I want to run, so I'd be content losing 300-400 MHz), but Dell of course does not want people doing that, and I didn't see anything in the bios in this guy to help... I'm pretty sure the dips in FPS I'm experiencing are due to a little thermal throttling, so would swapping in a 3 GHz P4 in that case reduce that issue? Or is that just the nature of P4's in general? I know they ran hot, but I don't know if that's just because I have a higher clocked one...

You could look around for a P4 with a lower TDP.

I'll look into the phase changing stuff for the thermal pad, I've heard about it, just seemed kind of messy to use. As for using a lower TDP Pentium 4 I think I may be out of luck... apparently the gx280 does not support Cedar Mill P4's, only Prescott, so my P4 650 at 84 W is as low as any Prescott can get 🙁

Also, it looks like there is not another fan header on the board from what I could see... this is turning out to be a lot tougher than I thought. Might just have to box this PC up for awhile and come back to it in a few years, maybe when some others have come up with better cooling solutions for these clamshell type Dells. Thanks everyone

Cedar Mill P4 651 at 65w is compatible with the GX280 - I have 3 of them running with those cpus, including one with the same case as yours.

I recently watched this YouTube video that talks about improving the cooling performance of this "clamshell" design: https://www.youtube.com/watch?v=00YUwq5_bn0

Towncivilian wrote on 2025-02-22, 16:12:

I recently watched this YouTube video that talks about improving the cooling performance of this "clamshell" design: https://www.youtube.com/watch?v=00YUwq5_bn0

good video.

Yeah that video was the one I was talking about having watched... Unfortunately, his is the SFF PSU, which is different than my PSU, so I don't think I can perform the mod he did by switching the fan direction... Plus, I think my fan is already positioned to draw in air anyways, based on an arrow etched on the PSU pointing from the exterior of the case into the computer's interior.

And I'll try giving that P4 651 a try StevOnehundred, if I can get a 65W working in my machine, then I think that would make a big difference on the thermal throttling under load. I don't know if there are motherboard revisions or other things to worry about for getting it to work, but I do have the last bios released already loaded (A08), so fingers crossed that it just works!

If anyone else has had experience getting lower TDP P4 CPU's working in these things (Less than 84W) definitely let me know. Love this site, thanks everyone

Yeah, these Dell desktop PCs always ran hot, pretty much no matter what you did to them.

According to the pictures you show, the PSU is drawing air from inside the case and exhausting it out. How I know? - The fan shown is a squirrel cage fan, and those can only push air towards their outer diameter... which means that if we can see the center hub, it's taking air from the case and pushing it into the PSU.

I think what makes it bad here is that there really aren't any appropriate air intakes. On top of the PSU fan taking air from inside the case and pushing it out, the CPU is doing the same thing... except, even worse here, the CPU is not fully pushing it out with that shroud, but allowing some to come back and re-circulate inside the case. But the cherry on top of it all: since there are no intakes (that I can see), part of the case vents that the CPU fan shroud pushes air out through is really the sole air intake vent. So essentially this thing is re-circulating a lot of its hot air.

One thing you can do is to remove the metal slot covers for the PCI covers. This should allow at least more air to come back from over the PSU side and towards the CPU / motherboard. Though looking at how closed-up that PCI riser board is, that might not help too much. If you're not going to use the PCI slots, then perhaps just get rid of the PCI riser board and its metal shroud. This should give the case considerably more holes to breathe from.

Next, the CPU heatsink... I see it's a 3-heatpipe unit, but judging by the size, I can tell you these things were never meant to cope with the full power of a Prescott CPU. These were designed towards an office environment type of job, so very likely the CPU reaches near or slightly over throttling temperatures. Now, since there really isn't space for anything bigger in there, the best thing you can really do is just look for a lower power Cedar Mill CPU.

As for under-volting the CPU... Dell's probably laughing their ass off, seeing how they locked up the BIOS. Probably the only way to do it is to look at the PWM driver IC for the CPU V_core and modify the resistor feedback network on the CPU VRM circuit. But that would be for someone experienced in electronics, really.

As for trying different thermal compounds - nah, I wouldn't waste time or money with that. Even the best one will not net you more than a degree or two max. The real issue is the hot CPU + small CPU heatsink + hot recirculating air inside the case.

That aside, it's worth noting that these machines were some of the worst from the bad cap era. Many of them suffered from failing Nichicon HM and HN caps. I doubt this would be the cause of the hickups in your system, but nevertheless I still suggest to check the caps on your motherboard carefully - particularly under that CPU fan shroud, as that's where the CPU VRM filtering caps are. Again, anything Nichicon HM and HN with a date code of H01xx, H02xx, H03xx, and H04xx is from the affected years of production (H01 = 2001 production year, H02 = 2002, and etc.)

RubDub2k wrote on 2025-02-22, 08:06:

This computer is from 2004, and I thought the most appropriate thing to run on a 2004 office computer would of course be... Half Life 2 (big surprise).

Hehe, that cracked me up. 😁
Also kind of reminds of how in CS_Office in Counter-Strike Source, those computers there were Dell Optiplex's... but the "minitower" versions... and dubbed "Beefy Computers". Not sure how beefy they are, but they always made for good target practice... and that much stands true for these small hot "shoeboxes".

Then again, I had the "pleasure" to work with the equivalent HP PCs at a small office I had an internship in... and I can't say HP did it any better.
I didn't have that good of an understanding of thermals back then, but even so I always wondered who (the heck) designed these cases and their poor airflow.

Wow, thanks momaka! I know I picked a pretty a pretty difficult project to tackle here with these 2001-2004 optiplex's, but I just find the look of them so goofy (in a good way). No longer are these computers the beige boxes of the 90s, but nor are they quite the "sleek black-and-silver" metal look of the late 2000s... just dark grey plastic in two tones, with a bit of the metal frame showing on occasion. That, and they are soft and rounded, which really make them stand out to me.

I didn't know that fan was called a squirrel cage fan, you learn something new every day! If it is pulling air from in the case tho, it's not doing a great job, but I suppose that's to be expected from an old mid-size office computer haha. And I tried looking into putting in another small fan in there, but unless I tap into the other fan header on the motherboard (there's only one header of course, thanks Dell), I wouldn't have any way to power it (easily).

As for the PCI slots, I don't plan to use both, but I was considering putting in a sound card in here. Not sure if it's really needed, as the onboard audio sound OK, but thought it could be a fun addition to make this thing truly an unassuming "Overkill" Win2k machine. Maybe I'll leave the other PCI slot uncovered... can't hurt too much, aside from a bit more dust.

And regarding the CPU, I did order that 65W variant of the Cedar Mill P4 651 (2006, SL9KE) which I assume is the one StevOnehundred was mentioning having success with in these models. I spent a ton of time confirming the graphics were working properly and not the issue (I lowered and raised the resolution and cut down and maximized the settings, and saw essentially no performance improvement at all and essentially identical frame dips at all those different settings in the same situations/game locations), and given the house-fan/open case test I did on the cpu, thermal throttling is the only thing that seems to make sense as to why I am experiencing such significant frame dips (consistent 70-300 suddenly down to 30-40 in some cases). So, hopefully the 65W vs 84W difference will provide at least some improvement... for the $14 I just spent on the Cedar Mill, I figured it couldn't hurt trying. And while I have a minor in electrical engineering, I am no professional and have only taken around 10 courses in the subject. Useful stuff for sure, but I just don't have the professional/real world experience to feel comfortable messing with motherboard circuitry aside from recapping a board or replacing damaged components.

And last, I did check the caps on the machine when buying it from a local guy, and I was surprised to see no leakage whatsoever. From what I could see, they weren't even bulging (if they were, it must have been very slightly). I did check the caps under the CPU fan shroud as well, and even those looked fine, which is why I paid $20 for it (I wouldn't have paid that much if I needed to recap it, I've only recapped once but it took me about an hour on a Dell Precision 390 with about 10 caps that needed replacing and cost me around $14 for solid polymer replacements). Perhaps when I swap in that P4 651 I'll check the cap dates like you suggested.

I'll update this thread once I install that P4 651 Cedar Mill so that anyone else running into this oddly exact or similarly related issue can reference it. If anyone else has any helpful stories/experiences related to this problem, feel free to share them in the meantime... the 651 is coming from China, so I got a few weeks to wait 🙁

I had a GX270 board with that same type of heatsink and fan on it. The GX270 is like an older version of the 280 - it's AGP with an i865 chipset and has the older mPGA478 CPU socket. It supports Prescott but the BIOS will underclock at POST if it detects the CPU is too fast, due to power draw.
My CPU was a Prescott 3.0GHz HT (mPGA478 version) which it did run at full speed. I was using an AGP Radeon HD2600 XT. That machine pumped out a lot of heat but I didn't notice any thermal throttling.

My motherboard was designed for that same type of case that you have. However, I didn't use that case, I had mine installed in a full size clamshell case instead (from some other model of Optiplex). The larger size case might have been the most important difference in the cooling, but of course it was also a slower version of the CPU. The heatsink/fan were still the original low profile hsf that came with it - I didn't have a larger heatsink that fit the board.

Yeah, I wish this PC was the larger mini-tower clamshell size you were talking about Shamino, but I haven't run into one of those in about 6 or 7 years... back then, I didn't know much about Windows 2000, so I didn't realize those early optiplex's had that much driver support for that OS. It wasn't until about the last year I decided to try and look for a PC that would run WIN2K well, and this is the best thing I've found so far 😒

Just gotta work with what I got, and if this Cedar Mill 651 I ordered works out well, then hopefully other people can try and use that trick to keep these smaller optiplex's from that time period from becoming ewaste 😀

RubDub2k wrote on 2025-02-23, 00:16:

And I tried looking into putting in another small fan in there, but unless I tap into the other fan header on the motherboard (there's only one header of course, thanks Dell), I wouldn't have any way to power it (easily).

No spare molex connector for an HDD?
If there is one, you could easily use that with an adapter (or do it the oldschool ghetto style and just shove the fan wires in the connector. 🤣 )
I'm not 100% sure about the Optiplex GX280, but the GX270 and older era ones don't have fan control on the motherboard's fan header. So if it's the same for the GX280 (I think it is, but I don't remember anymore), then there would be no point to try to power any fan from the motherboard's header.
Also, you can add fans, but the question is if they really will solve the imbalance issue between intake and exhaust airflow.

RubDub2k wrote on 2025-02-23, 00:16:

I spent a ton of time confirming the graphics were working properly and not the issue (I lowered and raised the resolution and cut down and maximized the settings, and saw essentially no performance improvement at all and essentially identical frame dips at all those different settings in the same situations/game locations), and given the house-fan/open case test I did on the cpu, thermal throttling is the only thing that seems to make sense as to why I am experiencing such significant frame dips (consistent 70-300 suddenly down to 30-40 in some cases).

Hmmm... that's an interesting bit of info there.
When you say the game starts to frame-dip, does that last for just a few seconds and triggered only by certain events on the map, or does it start to happen only after 10-20 minutes of gaming, when the CPU has had time to heat up?

Reason I ask is because I recall experiencing the former on a much more powerful system once or twice. I can't remember if it was on a high-end C2D (3 GHz) or newer C2Q (Q8300)... but it was very strange, because I remember it was a rather powerful system for HL2 game engine. Yet, every once in a while, I'd get these frame dips, sometimes even way below 20 and into the teens, triggered by something on the map (I can't remember if it was the gibs of some object or what.) But again, it was very strange behavior and only happened on that system. If that's what's happening to your game, then the Cedar Mill CPU won't solve this (but hey, at least you will still have a cooler PC? 😀 )

On the other hand, if your frame dips only happen after the CPU has had time to warm up, then that's more likely to be CPU throttling, especially if the framerate continues to stay low all the time afterwards, at least until you open the PC case.

Lastly, I don't remember how well the P4 architecture ran HL2... but to be honest, frame dips down to 30-40 FPS doesn't sound too abnormal for running the game on a CPU from that era. That said, rather than dealing with constant FPS changes and possible rubber-banding, perhaps consider limiting the framerate of the game either with something like RTSS (comes with MSI Afterburner), or just by using the command "fps_max xx" where xx is the framerate you want to limit too. I usually do 60 FPS if I'm running on an LCD monitor and 85 FPS if I'm gaming on a CRT. This will also off-load your GPU's power consumption a little, which in turn could also off-load the CPU a little as well.

RubDub2k wrote on 2025-02-23, 00:16:

Perhaps when I swap in that P4 651 I'll check the cap dates like you suggested.

Just check if they are Nichicon HM or HN series... and if they are, only then bother to check the date codes. If you have Rubycon MCZ or Panasonic FL, you probably won't have any issues (at least for now and the next however many years / a decade these caps are still good for.)

RubDub2k wrote on 2025-02-23, 00:16:

I'll update this thread once I install that P4 651 Cedar Mill so that anyone else running into this oddly exact or similarly related issue can reference it.

Awesome, thank you! 😀

RubDub2k wrote on 2025-02-23, 00:16:

the 651 is coming from China, so I got a few weeks to wait 🙁

You know, sometimes I really admire the thoughtfulness of the Chinese recyclers - instead of scrapping everything now as it comes, they seem to have saved / "put aside" some of the old computer parts somewhere, waiting for them to get old and more valuable again... which they have, somewhat ($10-15 is a lot better from a P4 CPU than $0.50-$1 it would produce in scrap precious metals.) Too bad they didn't think to do that with the older PCs from the 90's, particularly the 286, 386, and 486's. Then again, those contained a lot more gold and became worthless/obsolete too quick for anyone to anticipate one day these could be valuable. So it's a bit of a shame in that regard.

RubDub2k wrote on 2025-02-23, 00:16:

Wow, thanks momaka! I know I picked a pretty a pretty difficult project to tackle here with these 2001-2004 optiplex's, but I just find the look of them so goofy (in a good way). No longer are these computers the beige boxes of the 90s, but nor are they quite the "sleek black-and-silver" metal look of the late 2000s... just dark grey plastic in two tones, with a bit of the metal frame showing on occasion. That, and they are soft and rounded, which really make them stand out to me.

Hehe, yeah goofy is probably quite the right word to use, indeed.
I suppose I never paid that much attention to their looks... or alternatively said, they never stood out as anything special to me. Buy maybe that's their charm? 😀
Or maybe it's also because of the fact that I have two Optiplex (170L) and one Dimension (3000) machines from the same era, and I still use the two Optiplexes for basic web stuff sometimes, like posting on forums, email, and similar. One also has my entire MP3 collection and image/photo gallery, so it actually still sees quite frequent use. More importantly, that machine has been unstoppable ever since I got it. It served as a kiosk / desk PC in a local Park Police office from 2005-2011 or 2012. In late 2012, I got it and have been using it pretty much solely as my main PC from early 2013 until late 2023. It's been rock-solid in all of those years.

Now perhaps worth noting is that all of these are the regular "minitower" versions, so they do have more space inside and better cooling overall... but still far from great or even good. In particular, I have no problems with these machines in the winter, when the house temperatures are colder. In the summer, though, the fans will get annoyingly loud. Most of that is because there simply aren't enough air intake vents. Both the Optiplex 170L and Dimension 3000 have a 92mm exhaust fan + an 80 mm fan in the (ATX) PSU. Meanwhile, the intake is only comprised of two small vents on the front: one above the USB ports "nuk" and one under the front bezel. There's also a small vent on the back, next to the slot covers for the PCI cards... but really that's it. All three of these combined are not really enough for when the fans ramp up their speed in the summer. So what happens is the CPU fan starts to fight for air with the PSU fan, and they keep turning up and up to compete with each other. However, if I ever so slightly crack the side panel open on the bottom, the fans go back to normal low speed again.
Thus, even the larger Dell cases from that era are not great for cooling.

Yeah no spare power connectors for anything... there's one molex for the dvd drive, one FDD mini-molex (or whatever the name for the floppy power cable is), the motherboard power cable, the CPU power cable, and one SATA power cable (yeah, no IDE in this thing... High-Tech 2004 move. See the photo I attached of the power cable). Also, I redid the open-case, house-fan test again a bit better this time to see if that would make a bigger/better difference. I got the house fan blowing directly on the heat sink/ram and only a few inches away this time (it was like a foot away, don't have a lot of table space where I live to dedicate to my computer projects), and I honestly didn't notice much of an improvement over the last test, even though the fan is closer and now at a higher speed. I attached a photo of the fan setup as well, and I don't think I could have really gotten it any closer (it's a pretty solid fan, there's no shortage of airflow from that thing).

So I suppose maybe it isn't thermal throttling? It's still an improvement in-game, and I'm sure ordering the cooler 651 Cedear Mill wasn't a bad idea for the system (assuming it works), but the FPS improvement is only like 15%, maybe 20% tops. There are a couple of areas in game that drop down into the 40s and upper 30s still, even with VSync on and this fan setup. This lasts as long as I am in that area, usually it's when I look a certain direction and am outdoors (I don't know how much half life 2 people have played here, but it's in the beginning of the game when you are starting to navigate through the canals and fight the combine). As long as I stay looking at some part of the map, the FPS will just be low. I turn 90 degrees without moving, then I'm back at 60 (without VSync, easily 90-120). Barrel explosions also cause frame drop issues too, but even after killing the combine and having no AI or explosions, I still can get those low 40s fps depending on location. Some areas are fine, but some really struggle.

I'm honestly at a bit of a loss... The recommended (not minimum, those ones are lower than these) system requirements (from gamesystemrequirements.com and on the original box) are:

CPU: 2.4 GHz Processor
RAM: 512MB RAM
GPU: DirectX 9 level Graphics Card
OS: Windows XP/2000/Me/98

And my system's at:

CPU: P4 650 (3.4 GHz, Hyper Threading)
RAM: 3GB DDR2
GPU: 1GB DDR3 Radeon HD 5570 (Sapphire, Low Profile edition, from 2010)
HDD: 120 GB SATA III SSD
OS: Windows 2000 (Unofficial SP5.1, Unofficial Kernel Extension by BlackWingCat)

I feel I've pretty confidently ruled out the GPU and operating system at this point and concluded it must be otherwise hardware bound... I was very young when this game came out, so I didn't really play it until well beyond the Pentium 4 era. Are these frame drops just part of the Pentium 4 experience then? Was that considered normal back then to have your game fluctuate between 30-60 fps on high-end hardware? I have a 2006 core Duo iMac (not core 2 duo) that I need to install an ssd in, so perhaps I'll try dual booting windows xp on that machine and see how it performs. Like I said earlier, I tested this build of half life 2 on another computer with a first gen i5, 12gb of ddr3, and windows vista, and had no frame drop issues whatsoever.

I suppose this is part of the learning process... this is the first pentium 4 system I have worked on, so I don't know what's normal and what's not. Thanks for the advice everyone.

momaka wrote on 2025-02-23, 20:31:

Just check if they are Nichicon HM or HN series... and if they are, only then bother to check the date codes. If you have Rubycon MCZ or Panasonic FL, you probably won't have any issues (at least for now and the next however many years / a decade these caps are still good for.)

While I had the case open there for the CPU test, I looked and the only non-informational lettering on them I saw was "FL", so perhaps I avoided being scathed by the capacitor plague... and to be honest, they look pretty good too, no leakage or any obvious bulging, even the ones underneath the cpu fan/heatsink.

momaka wrote on 2025-02-23, 20:31:

You know, sometimes I really admire the thoughtfulness of the Chinese recyclers - instead of scrapping everything now as it comes, they seem to have saved / "put aside" some of the old computer parts somewhere, waiting for them to get old and more valuable again... which they have, somewhat ($10-15 is a lot better from a P4 CPU than $0.50-$1 it would produce in scrap precious metals.) Too bad they didn't think to do that with the older PCs from the 90's, particularly the 286, 386, and 486's. Then again, those contained a lot more gold and became worthless/obsolete too quick for anyone to anticipate one day these could be valuable. So it's a bit of a shame in that regard.

And I agree with that, it does make me happy that some people out there are actually taking the time to resell these old parts. It is unfortunate that finding those older computer parts is so difficult... I haven't dabbled in 286, 386 or 486 PC's much, but I am strongly against e-waste. There is so much that can still be done with these systems, but that's the downside with fast-moving tech I suppose 😒

Cheers,

RubDub

Sooo, that system probably had the motherboard replaced during the capacitor plague. There is absolutely no other way for a SX/GX260,270, or 280 to not have bulging capacitors unless somebody replaced the motherboard or the capacitors.

I worked doing onsite warranty repair for a Dell contractor during that fiasco. We were replacing hundreds of them a week for a while.