I am trying to build a Craftsman tool case portabale computer and I need to know how to figure what size PSU to use?

I am using a MU440EX Motherboard from year 2000. I know it is an old board but it has never been opened until today and I know that because I cut the factory seal on it.

It says the Pentium 11 processor is supporting a host bus frequency of 66 MHz. The supported Pentium 11 processor have clock speeds of 233 MHz, 266 MHz, 300z, and 366MHz.

Intel Celeron Processor supporting bus speed frequency of 66 MHz. The supported Celeron Processor has a clock speed of 266 MHz.

As you might already know that it supports SDRAM DIMM
* 168 Pin 3.3V DIMMs with gold plated contacts
*  66MHz  4- clock unbuffered SDRAM
*  non-ECC (64-BIT) memory
*  Serial presence detect (SPD) or non-SPD memory
*  8 MB, 16 MB, 32MB, 64MB, and 128 MB modules

First question- I have a Pentium Processor so will it work without being a Pentium 11 ?
I do have a 233 MHz and a 266MHz and I think I have a 300MHz INTEL Pentium 11 Processors so can I put any one of the in it and then set the BIOS for the speed Processor? Would any of them work as long as the BIOS are set to the correct one?

Second question is how do I know what WATTAGE of PSU should I use with this system? I have a 230W system with a on/off switch already hooked in to it from the factory that I am thinking of using but I do have a big supply of all different wattage boxes that I can use if it will not hurt it. I don't know how high I can take it.

I am getting pic's so I can try and make an Instructable for the first time to when it is done so I can see what all of you think about it.

I might be replying back again later when I get to the BIOS part unless I get it done on my own. Cross your fingers for me I will need all the luck I can get being my first time and all.

Please answer back with the cold hearted truth so if I do make a mistake that will be the only way I will know it.

Thanks to you all


Burf7 years ago
Here is a link to a nice guide that will answer most, if not all, of your questions.


I have built two PC's myself but I started with a ready made case and p/s. The first one was a little scary because I had no idea what I was doing. I used a guide similar to this one, unfortunately, that particular guide seems to no longer exist.
The second one was easy, having had the previous experience.
 I recommend you put together a parts list before you do anything else, checking for compatibility and making sure that you have everything you need, prior to picking up a tool.
Plan first , then assemble.

lemonie7 years ago
Processors usually configure themselves automatically, you ought not to have to do any more than fit it (correctly).
I doubt the Pentium would work (even if it fits) in a PII board, the chip architecture is different enough that they changed the name significantly.
The wattage you need would be the sum of all your parts' requirements, plus a bit more. Check the power rating of the GPU and average consumption for drives etc. 230W sounds a bit weedy if this were to be used for anything CPU & GPU intensive.