I just installed linux on my old xps 200 and the fans are running really loudly. Is there anything i can do to make it run quieter or is my computer simply too old?

From what I can see, the xps 200 is a SFF P4 with up to 3 internal fans (PSU heatsink fan, CPU fan, GPU fan).

If it is noiser under linux than it was with windows, you might need to check some of the software you are using. If its as noisy under linux as it was with windows, you should check the BIOS fan settings, you might be able to slow the fan down.

Its also possible (likely, really) that the one of the fans is old enough that its getting noisy (or it was a cheap and nasty fan and was always loud). You should be able to replace the fans. If its the PSU fan that is noisy it wont be fun. GPU fan, I'd almost consider getting a new 1/2 height video card that is passsive cooled. CPU fan, shouldnt be that hard. But how hard it is to replace the fans will depend on how much experience you have with hardware.

There is also the other option, using some soundproofing inside the case. Being a SFF you wont have much room though, and those P4s used a lot bit of energy and ran pretty hot, so be careful not to block airflow if you do decide to use some soundproofing.

I have zero experience with any of that looks like i got some learning to do.

• probably, at least one fan is a bigger contributor to noise than the others; that is where the 'biggest bang per buck' lies
• if the power supply is noisy, think about replacing the whole power supply; a decent replacement (as opposed to the lowest cost replacement that you can find) will probably be more efficient as well as quieter. It is probably only worth taking this path if the power supply is a standard sized unit, and that isn't always the case in these SFF units
• In principle, the CPU fan would be easy; in practice pulling the motherboard to get access can be a learning experience...primarily learning which swearing works and which doesn't

There are suppliers (eg, silentpc) who specialise in low noise PCs and parts, and maybe you could get a recommendation from a local 'quiet PC bits' supplier as to low noise parts.

I can think about another possibility. If you had installed the Dell OEM version of Windows on it before, it may be possible that an application for controlling the fans was installed on it.
May be you can get the machine quieter with using software like fancontrol and/or pwmconfig. May be worth a try, but keep an eye at the temperatures.

Download a Manual for your mainboard or go into BIOS to see what can be configured. If I remember correctly only 4 wire fans can be run at different speeds. There are also external circuits that can be added that adjust fan speeds. Like the other posters state ,software can also be used to accomplish this.

Yes and no. Pukka control requires 4 wires -- two power voltage, one fan speed sensor and one control input -- but many motherboard fan headers are wired to control the power voltage.

I am currently controlling 3 wire fans on 4 pin headers using lm-sensors' fancontrol script.