underclocking an old pentium 200

[TdB]

im am trying to build a computer for all my old dosgames out of all the old hardware that was scattered around the house:

it has the following specs:

pentium 200mhz

64 mb ram(don´t know exactly what kind of ram, the kind the was normal before edo-ram)

panasonic floppy drive

abit ab-pr5 motherboard

seagate 1248 mb harddisk

soundblaster awe 64 gold

matrox mystique 4mb ram(with ram-upgrade)

nokia 21" monitor

enermax psu (with broken fan)

mini tower AT cabinet

I haven´t found a cdrom drive yet, Im working on it

ms dos 6.22

the only real problem is the broken fan on the psu, it is very hard to find a old compatible psu in the stores nowadays, so i was thinking about underclocking the cpu, and hope the cpu cooler would be effective enough(most dos-games doesn´t need 200 mhz anyway).

now, the question is how should I determine if it will work, how does an old pentium respond to heatproblems? does it just power-off without any damage or does it burst in flames, or is it just unstable?
I don´t have any equipment to measure the temperature on the cpu.

another question is what i should try to underclock? if I only underclock the cpu I can get it down to 100 mhz and still keep the fsb at 66 mhz (1.5 * 66) or does the rest of the motherboard generate so much heat that it would make sense to run it at 75 mhz (1.5 * 50) with a fsb at 50 mhz (the cpu multiplyer won´t go lower than 1.5).

do any of you guys have any experience in underclocking old computers, and is able to provided me with some input and advices?

[Guru]

AT PSUs are not that hard to come by (~20-40€ for a 250w) but why don't you just change the fan in the old PSU?

[TdB]

I don´t have a spare fan, doesnt PSU´s need special fans???

so far I have only checked danish online stores and they don´t sell AT PSU´s AFAICS.

BTW, how many watts should an optimal PSU for my dos-system have?


edit I just found one: http://www.qtec.info/products/product.htm?artnr=13232

a 200 watt PSU.

is that powerfull enough for a p200 ?

[Guru]

I don´t have a spare fan, doesnt PSU´s need special fans???

No!

BTW, how many watts should an optimal PSU for my dos-system have?

Optimal? 1000 MW!

edit I just found one: http://www.qtec.info/products/product.htm?artnr=13232

a 200 watt PSU.

is that powerfull enough for a p200 ?

Yes!

[Novdid]

You can use a standard 80mm fan to swap out the one that's not working.

[Ribbit]

Re: underclocking an old pentium 200

Originally posted by TDB
(don´t know exactly what kind of ram, the kind the was normal before edo-ram)

/me pokes head round doorway:

It was called FPM (Fast-Page Mode) ram.

/me goes back to whatever I was doing before...

[TdB]

well, I wasn´t exactly a hardware enthusiast back then(I just played the games)

[Technoid]

I became hardware aware becuse my computer didn't play the games I wanted

[KvHagedorn]

PC Power and Cooling sells slim or regular AT power supplies online. May be a bit more than you want to spend, but the thing will probably last for many years. These guys make excellent products.

http://www.pcpowercooling.com/

The price isnt as bad as I thought. $39.00 for a 230 watt slim. There is also a higher end Turbo-Cool 300 watt slim for $75.00, and a 400 watt for $169.00.

[thop]

FPM has usually -70 (70ns) on the chips, and EDO usually -60 (60ns). theres also FPM at 60ns, but no EDO at 70ns.

[Byock]

True, Luckily at 200mhz it should be new enough that you don't need to worry about Parity and non Parity memory. Hmm, I think I still have some 1 meg 30 pin simms around here somewhere.

[Chrono_Wanderer]

Originally posted by Guru
Optimal? 1000 MW!

For DOS must to be a huge Pentium II

[KvHagedorn]

Originally posted by Guru

Optimal? 1000 MW!

Yeah, really.. actually the surges from such a massive thing would probably fry everything on the board! And your electric bill? Heh..

[Guru]

A 1000MW PSU would most likley require it's own atomic plant yes whats your point!

[Wombat]

My biggest problem is that on a good day you'll get 80% efficiency. 200MW of waste heat!!!!