That Northwood isn't that particularly hot running as far as a P4 is concerned. But as long as you have at least one intake and exhaust you should be good. The only real way to know would be build the system and monitor your temps.

We need to see what the final 'insides' of your machine and the side panel look like to provide the best advice. In all likelihood, you're going to be fine with just a rear exhaust fan, but I'm presuming you'd like to have the most effective setup possible.

Are you using a stock Pentium 4 heatsink/cooler? Without knowing where the power supply and processor are installed in the case, my initial reaction is to make the side panel an exhaust fan and the rear fan as intake. Otherwise, the Pentium 4 fan would be pushing hot air into incoming cool air resulting in turbulence and less effective cooling.

If the power supply is sitting above the processor and near the rear case fan this will change my advice (since it will also be an exhaust fan and pull the incoming cool air up and right out of the case). If you're using an aftermarket tower/cooler with the exhaust pointing toward the rear, then making the side panel an intake fan and the rear case fan an exhaust fan would make more sense.

If there is no airflow assisting the Ti4400 fan, this is also something to be address.

Let's see what you have, tell us your plans for this setup, and what you think is the best airflow design for your needs, and we can chime in with any tweaks, if necessary.

Meatball wrote on 2022-05-02, 20:03:

We need to see what the final 'insides' of your machine and the side panel look like to provide the best advice. In all likelih […]
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We need to see what the final 'insides' of your machine and the side panel look like to provide the best advice. In all likelihood, you're going to be fine with just a rear exhaust fan, but I'm presuming you'd like to have the most effective setup possible.

Are you using a stock Pentium 4 heatsink/cooler? Without knowing where the power supply and processor are installed in the case, my initial reaction is to make the side panel an exhaust fan and the rear fan as intake. Otherwise, the Pentium 4 fan would be pushing hot air into incoming cool air resulting in turbulence and less effective cooling.

If the power supply is sitting above the processor and near the rear case fan this will change my advice (since it will also be an exhaust fan and pull the incoming cool air up and right out of the case). If you're using an aftermarket tower/cooler with the exhaust pointing toward the rear, then making the side panel an intake fan and the rear case fan an exhaust fan would make more sense.

If there is no airflow assisting the Ti4400 fan, this is also something to be address.

Let's see what you have, tell us your plans for this setup, and what you think is the best airflow design for your needs, and we can chime in with any tweaks, if necessary.

I'm building the system right now and there are still a few parts missing so I don't think a picture right now will help, as the system is not ready. But the PSU is above the processor and the cooler for the processor is an aftermarket Pentium 4 cooler and its quite similar to the stock Pentium 4 cooler.

I'm trying to make it a windows 98 gaming PC to play games like, system shock 2, thief etc...

no

also, you realize that the P4 is well within the age of CPU temperature sensors? So what's the question to you?

Cuttoon wrote on 2022-05-03, 05:21:

also, you realize that the P4 is well within the age of CPU temperature sensors? So what's the question to you?

If I need an intake fan or not for a PC like that?

eyalk4567 wrote on 2022-05-03, 09:44:

Cuttoon wrote on 2022-05-03, 05:21:

also, you realize that the P4 is well within the age of CPU temperature sensors? So what's the question to you?

If I need an intake fan or not for a PC like that?

Fair enough. 😀

Just make sure the PSU fan works. And since that is mainly to serve the PSU itself and often temperature controlled to do just that, install one more that evacuates air from the case, out back, if there's a spot for that.

Then, there needs to be some way for air to enter up front and from the lower half of the case: Any case from 2000+ will have sufficient openings in the lower front and many on the sides.
- Since a P4 system is ATX, the case will be ca. 1998 or newer, so I'm pretty sure it's just fine in that respect.
Additionally, you could get serrated slot brackets on the unpopulated slots for some additional intake - that's a good idea next to the graphics card.
Since the fans on the back will lower the pressure in the case, atmospheric pressure will take care of the rest.

There are only a few temperature critical parts in a PC. Some will cause instability if too hot, some may live longer if not:
- PSU
- CPU
- GPU
- motherboard northbridge
- voltage regulators on Mainboard, PSU or other parts
- RAM on motherboard and VGA, to a much lower extend

Most motherboards of that time will have at least two temperature sensors, CPU and case. Those get displayed in the BIOS setup, somewhere under "power management" or "PC health" or similar names.
40 °C is usually nothing to worry about for the inside of the case, 60 °C for the CPU - apart from that, CPUs have official specification. Since P4s aren't rare or expensive, there's little incentive to run it below its safe/stable temperature, as long as you don't want to overclock it.
There's a temp sensor in harddrives of that time, that's called the smart function and may be displayed in Windows or with certain tools in Windows or tools from the respective manufacturer like "seatools" for seagate drives, etc. Again, beyond the data on that drive, not really critical.

Even many 2000+ GPU should have a temp sensor, readable with certain tools like the riva tuner or included in manufacturer drivers, IIRC. But if 3D runs stable, it's probably fine.
There should be some basic airflow to the array of voltage regulators on the mainboard - usually taken care of by the CPU fan and the little gaps in the ATX backplate.

So, roughly, as long as case temp stays below 50°C and all the other sensors within specification, there's really no reason to worry.

That's how you know you have sufficient ventilation - it's not about the fan count. 😉

eyalk4567 wrote on 2022-05-03, 09:44:

Cuttoon wrote on 2022-05-03, 05:21:

also, you realize that the P4 is well within the age of CPU temperature sensors? So what's the question to you?

If I need an intake fan or not for a PC like that?

I would definitely add at least 1 case fan to any P4 rig. If you don't, all the hot air will run through the PSU which will not only be detrimental to the cooling of the parts used for the build inside of the case (run hotter and make more noise and possibly increased slowness and instability and faster aging of the parts used) but also to the PSU as well (which will also age faster).
Case fans are relatively cheap, there's little reason to skip it unless the case itself doesn't lend itself to adding a fan. But in such a case I wouldn't want to use that case for a P4 anyway.

Regarding your original question

So my question is, do I need for a Pentium 4 pc a front intake fan or can I just put one on the side panel?

I don't think this really matters? You could add both or try both spots and measure temps. It's hard for us to judge what the effect will be if we don't even know what your system physically looks like.

eyalk4567 wrote on 2022-05-02, 18:56:

I got an old case for a Pentium 4 build that I'm doing right now. But the front of the case doesn't have anyplace for an intake fan in the front, only on the side.

When your build is operational and runs too hot you can always add a harddisk cooler to an empty bay in the front:
https://www.performance-pcs.com/fans-accessor … c-hk-3f-bk.html

eyalk4567 wrote on 2022-05-02, 18:56:

[...]

So my question is, do I need for a Pentium 4 pc a front intake fan or can I just put one on the side panel?

Neither. If you need one fan, it should be an outtake fan and it should be high in the case (either behind the CPU, or straight out the top).

It's important for airflow to have underpressure in the case, not overpressure. That means you always want more outtake than intake. A default ATX setup without case fans has an outtake fan in the PSU, so achieves this. If you add one casefan, it should also be outtake. Only if you also add a second casefan does it make sense for it to be intake, not outtake.

Whatever you do, don't add an outtake fan low in the case, as that would prevent cool air from the bottom or front of the case reaching the CPU higher in the case.

And as for whether you need an extra fan in the first case - check the case temperature when all closed up. If that's say <35C I'd say you're fine. If significantly hotter, you need that fan. Without knowing the design of the case, how messy the insides are and the environment it will have to work in (temperature, free space around air vents), it's not possible to give you an a priori answer.

Thank you all for all the information you have given, it really helped 😀