The basis: mainboard bundle

Looks like some good components.
Make sure all your RAM sticks are the same speed for best performance
Looks like a Good motherboard but the Barrel battery could burst and leak acid onto the motherboard in the future.
I would cut it off and add a coin battery holder.
1mb video card is good enough. Maybe a Cirrus logic VLB 5428 or 5429 but I did have a Trident SVGA VLB card back in 1995
To run Win95 and it worked good for Win3x and Win95 with a SVGA monitor
I would get a Fast CDROM like the Sony 52x
CF card is good idea
64kb or 256kb of Motherbard cache is Good enough.
If you really want to improve speed and performance get an Intel Overdrive CPU like 486dx4-100 or Pentium Overdrive 83mhz

I have my 486dx-100 running with just 3mb of RAM and it plays most games.
You only need more memory when running Win3x or Win95

Make sure to configure you Device drivers to load HIGH in config.sys

The case.
It's not marked with any famous brand, but it has a sticker at the back from a former local computer store...

Further pictures from the inside.
In one of these pictures, you can see the little battery box next to the L2 cache. It is connected with a wire to the mainboards external battery header.

Turbo off mode = equivalent to a 486 SX (20Mhz)

Turbo on mode - 66Mhz

Speedsys results.
Are these values comparable to your 486DX2 values?

Further benchmark results (with Phil's DOS benchmark package).

3Dmarks 1.0
43.4
3Dmarks 1.0c
42.8
PCplayer benchmark (320x200)
10.2
DOOM (full screen benchmark)
3068 realticks = 24.345 fps

I really like this
Especially the slow CD-ROM
Everything is very clean and fits good together
👍

Can you do NSSI benchmark in turbo mode?

Here are some NSSI screenshots with fastest and slowest settings (exclude L1 and L2 cache disable method....). Previous shown benchmark values are with fastest ram timing.

Overview

CPU benchmark NSSI, 66MHz (Turbo ON), fastest ram timings.

FPU benchmark NSSI, 66MHz (Turbo ON), fastest ram timings.

CPU benchmark NSSI, ~20MHz (Turbo OFF), slowest ram timings.

FPU benchmark NSSI, ~20MHz (Turbo OFF), slowest ram timings.

Here further values from Phil's benchmark list, with 486-sx 20 speed @low ram timings
3Dmark 1.0 , 16.3 fps
3Dmark 1.0c , 16.2 fps
PCplayer benchmark (320x200) , 3.6 fps
DOOM (full screen benchmark) 9407 realticks = 7.94 fps

486/66 VLB, the very definition of a 486 in my book! 😀

I never liked sideways floppy drives, but that's just personal taste and no loner care that I mostly use goteks.
I DO like the Mhz display, something I'm still lacking in my collection.
And agree those old Creative drives really add to the feel of an old 486.

My 486dx4-100 does 20mhz too with the turbo button turned off.

Back in 1995, 486 hardware was still expensive

Examples:
486dx4-100 cost $150
VLB motherboard cost $120
1mb of RAM cost $100
2x CDROM drive cost $150
Sound Blaster cost $150
SVGA card cost $100 and up

I had an All ISA computer back then. A 486dx-33 with 4mb of memory and cheap Oak SVGA card, Sony 2x CDROM
And Sound blaster compatible sound card.

I Had this computer built by a computer company for about $2000
Manufactures like IBM PS/1 were selling this Spec computer from $3000

I had mine built in 1993 when DOS 5.0 and Win3x was the latest Operating systems.
My friend helped me choose the components for my 486 computer.
We read magazines and choose the best value components of the time to closely match the IBM PS/1 computer.

We thought this computer would last for ever.
Two years later Microsoft came out with Windows 1995 and this is where my Nightmare in Upgrading computers started.
My computer was to Slow to run Win-95. It would install but took forever and when finished it ran Win-95 very slow and poorly.

So I had to upgrade my computer to be able to run Win-95

I purchased hardware:
486dx-50mhz
VLB motherboard
VLB controller card
VLB Trident Video card
4x Mitsumi CDROM
And 4 more sticks of RAM

This hardware upgrade cost about $400
The RAM I bought used for $50 each
Most of the components I bought used for half the price of New.

So I upgraded my computer and installed Win-95
It installed much faster now and ran Win-95 okay.

I kept this build for a few years and later purchased an AMD 5x86-133 with Plugn-play PCI Motherboard combo for about $120
This is what computer stores were selling to people who wanted to upgrade their old computers to be able to run
Win-95

So It was a BIG Expensive Mess upgrading computers for Win-95
You Needed Plug-n-play hardware with all the latest technologies and bios

Very cool build and awesome looking case. I had the same board in my 486DX build back in the early 90s. Unfortunately it didn't survive a leaking battery but I still have it.

Nice! A 486 DX2 with VLB was my families first PC. Built one myself last year because of the compulsion. Been playing a ton of Master of Orion on it.

I think your Doom benchmark almost exactly matches mine. You should try Fastdoom though. Took my benchmark from 3000ish realticks down to 2000ish. Not that Doom runs bad on a DX2, but fastdoom makes it buttery smooth.

Ultimately to get the most out of a 486 CPU you want to use one of those PCI/ISA Plug=n-play motherboards with NEW Bios.
I have seen benchmark scores using the same CPU on PCI motherboards vs. ISA vs. VLB
With the PCI motherboards you can get about a 20 to 30 percent performance increase.
It also uses more and faster RAM.

Thats if you want to get the most out of your 486 computer.

These were very popular upgrades for 486 computers to run Win-95