Hello everyone, sorry for not being that active, I had a rough time with the passing of a close family member, it did take me some time to get back in to it again.
But finally I was able to upgrade the Slot A build to something far more proper, I added the following parts just to perfect the system and make it more optimized for it's timeline of Mid 2000.
AMD K7 Athlon Thunderbird 900Mhz for Slot A
2x Noctua NF-A6x15 FLX 60x60x15mm fans
3dfx Voodoo3 3000 PCI 16MB with 5.5ns 128Bit SK Hynix SDRAM Rev.A 4599
And here the final setup of this Year 2000 AMD Dream Machine
Nighthawk
AMD K7 Athlon Thunderbird 900Mhz Slot A Undervolted to 1.60v CPU voltage
3x 256MB PC-133 Legend / Hynix @ PC-100
MSI MS-6195 AMD Irongate AM751 Chipset
ATi Radeon AGP 64MB 128Bit DDR Rev.C1 0111
3dfx Voodoo 3 3000 PCI 16MB 128Bit SDR Rev.A 4599 with 5.5ns SK Hynix SDRAM
Vantec Cooling Spectrum Slot cooler card for Radeon AGP 64MB DDR, well currently.
Samsung 3.5" FDD Drive
1x 40GB Western Digital Caviar SE WD400EB 7200 rpm HDD Main drive + 8MB Cache
1x 80GB Western Digital Caviar SE WD800JB 7200 rpm HDD Slave drive + 8MB Cache
Plextor PX-760A 16x/8x DVD-RW / 48x / 24x CD-RW UATA-133 Drive
NEC ND-3500A DL-DVD-RW 16x SL-DVD-RW / 4x DL-DVD-RW / 48X CD-RW Drive
NEC 5 port USB 2.0 PCI Card + Front Panel 3 in PCI Card 2 in Front Panel
Intel Pro 100/S Desktop Adapter PCI (10/100Mbit Ethernet PCI Card)
Creative Labs Sound Blaster AWE64 Gold CT4390 4MB ISA PCB Date 3197
(Gold Recap done for CT4390 by by Backfire from Voodoo Alert Forums, Germany)
2002 A-Open H-600-B ATX Case
A-Open 350 Watt PSU or equivalent.
Compaq S710 17" Blackshade CRT from 2001
Reso @ 1024x768x32 @ 85Hz | 0.22.5 Dot Pitch
Win2K Pro UK + SP4 & RU-01 for SP4
ATi Catalyst 6.4 for Win2K/XP
AmigaSport 3.0 for Win2K/XP for V3 3K PCI
So here the pics of this beauty that is finally completed:
Here the CPU with the two Noctua fans mounted on it's brass colored heatsink, screws all are different I used what I ahd laying around, it's gives cool Makeshift look rofl
Here the two graphics cards:
ATi Radeon AGP 64MB 128Bit DDR Rev.C1 0111
3dfx Voodoo 3 3000 PCI 16MB 128Bit SDR Rev.A 4599 with 5.5ns SK Hynix SDRAM
Here I set the CPU voltage from 1.75 volts to1.60 volts and ran Prime95 Torture test for 9 hours and 7 minutes, all tests were passed and no errors were reported:
Here a test out of curiosity at 1.55 Volts, at first I was like haha! this won't last long, but surprisingly the system ran Prime95 Torture Test for 2 hours and 6 minutes, passing all tests and also no reported errors, this did impress me that my K7 TB 900 has a very high quality die:
But when I wanted to reboot, just because why not, the system hanged and the monitor went black, so after turning off the system and discharging the PSU and then turning it on and going back to the Bios I set the CPU back to 1.60v and all is great again, I played Star Wars Dark Forces II Jedi Knight for a good 4 hours flat with the ATi Radeon AGP 64MB 128Bit DDR ViVo Retail @ 1024x768x32 + FSAA x4 & AF x16 without any issues a nice heavy test but it ran the game like no tomorrow.
So yea this did prove me that with the CPU voltage set to 1.60volts that the system is stable under all workloads, this will make the CPU less hot under long term work loads and this also helps put less strain on the +5 Volt Rail of the Power Supply Unit, well as how I was informed.
This hobby does help my mental state a lot, it helps me focus on positive things more 8)
Nice system! Undervolting the CPU is a neat trick indeed. It's possible on many CPUs but on a Slot A system it really helps in controlling heat 
.