As a first approach you'd pull out everything but the bare minimum required to run the games. Cleaning contacts wouldn't be a bad idea either.
To test the memory you can try memtest86+.

It's good for DOS gaming, but don't expect it to pull off any newer win9x games. Btw, why is the CPU underclocked?

Well the project started as a DOS gaming rig and I was aiming to low-mid end Pentium performance class. I was hoping that with lower clock combined with enabling and disabling primary and secondary caches, I could play around all 386 - Pentium era DOS games, even the old speed critical ones. It was only after I decided to add the Voodoo 2 (I had never before played Glide games, save some experiments with wrappers) to the mix that I made up my mind installing Windows and not just DOS.

I might disable the underclocking because in the games I plan to play and have tested so far, only Ultima VII seems to be speed critical and even then it seems too fast @200 MHz and caches disabled. The ideal speed margin for this game seems to be quite narrow (it seems to run either too slow or fast), plus it is a bit of pain requiring different boot (no EMM386). So I might use DosBox on my Core2 machine for that.

I was even considering doing some kind of poor man's turbo button so that I could set the jumpers for the clock frequency without opening the cover of the PC. Didn't come up with any good idea on how to implement that yet though. Has anyone done this kind of switch(es)?

ufoufo512 wrote:

Well the project started as a DOS gaming rig and I was aiming to low-mid end Pentium performance class. I was hoping that with lower clock combined with enabling and disabling primary and secondary caches, I could play around all 386 - Pentium era DOS games, even the old speed critical ones. It was only after I decided to add the Voodoo 2 (I had never before played Glide games, save some experiments with wrappers) to the mix that I made up my mind installing Windows and not just DOS.

I might disable the underclocking because in the games I plan to play and have tested so far, only Ultima VII seems to be speed critical and even then it seems too fast @200 MHz and caches disabled. The ideal speed margin for this game seems to be quite narrow (it seems to run either too slow or fast), plus it is a bit of pain requiring different boot (no EMM386). So I might use DosBox on my Core2 machine for that.

IIRC "Ultima Collection" is shipped with Mo'Slo Deluxe, and combining an underclocked PII with Mo'Slo might be a good alternative to DOSBox (some titles have problem with Mo'Slo + a CPU faster than 200MHz).

From the series, i only have Ultima VIII and it ran fine on a PIII 450 (cache disabled, don't remember the exact setup though)

I was even considering doing some kind of poor man's turbo button so that I could set the jumpers for the clock frequency without opening the cover of the PC. Didn't come up with any good idea on how to implement that yet though. Has anyone done this kind of switch(es)?

Thought about that too (switches for multiplier and FSB), but haven't really looked into it. A user here has done that to his Super Socket 7 rig or something.

There are plenty free programs out there. Have you any prior experience with those?
For testing your ram I can recommend memtest86.
For global info there are tons of programs available like PCWizard, Sisoft Sandra, Everest, HWMonitor and many more.

And about cleaning contacts, it's what I always do first before putting a system together.
I'll usually clean the contacts of expansion cards, ram modules and slot 1 cpu's.
I'll also clean the pc case, the interior of the PSU (and check if theres any bulging caps or other visible damages) and after mounting a cooler with some fresh cpu paste, let it run and watch the cpu temp from within the BIOS if it goes up by a lot in say 15 minutes.
Also I always make sure theres enough ventilation in the case. Usually I'll carefully pick a case before actually putting any hardware inside it.
This is important as you can't just buy a second hand P2 and put a Core2Quad with SLI inside as the case likely can't provide enough cooling for the rig.
Also make sure your PSU can handle your computer. A 200W PSU is probably a bad idea with, say, an Athlon XP 2000 Palomino, a GF5800 or Radeon 9800, some overclocked ram and a crappy old case without an exhaust fan.

Just throwing some parts together without some planning will mean that any vague problem could be caused by anything.