That CPU is fine.
A 486dx2-66 would be a little better in performance.
A 486dx4-100 Overdrive CPU is only going to get you about 10% boost over the 486dx2-66
8mb is fine for DOS but Win3x can handle up to 32mb
So you want at least 16mb for Win3x
See if you can upgrade the motherboard video ram to 2mb or get a dedicated video card with 2mb. ( Tseng ET4000 )
Upgrade the motherboard cache to 256kb.
Replace the motherboard battery.

I have a couple of these AST Bravo 486 computers.
Originally they came with a “Media Vision PAS16” sound card and Sony 2x CDROM drive.
They sold with 4mb of ram and 64kb cache.
Not very good for a Multimedia computer.

Unless you are a AST enthusiast these computers are difficult to work with.

Reason
The Battery is soldered on
Onboard video is not that great.
The motherboards are there own design and strange bios.
I found it hard to upgrade these computers.
I do like the nice case design however. Very clean looking.

I would not waist to much money on it.

Think the above is a bit harsh.

The link above doesn't work based on the motherboard number think this is the page your looking at?
https://stason.org/TULARC/pc/motherboards/A/A … 202594-XXX.html

If it is then its a coin battery which is better better then a Dallas RTC, neither are a deal breaker on a 486

It has PS2 ports, common on OEM 486 motherboards, much less common on generic motherboards

The onboard video would be using the VL-bus. That'll save you fair bit of money, I'm struggling to find out which chip is uses though.
How much memory does the video card have? looks like 512k or 1MB by default , upgrading can be difficult due to finding the right modules and 512k is fine for dos. more will allow higher resolutions in windows.

How much cache? you do want to upgrade this to 256kb
Ram you can upgrade upto 64MB this is what I do, partly to simply max out the motherboard but I also find having a RAM drive is handy as well. The optimal amount of ram will depend on your cache size.

It doesn't look like the motherboard supports 3.3v limiting you to 5v CPU's.
Upgrading from 50Mhz to 66 isn't really worth it IMHO which just leaves the Pentium Overdrive. I agree the performance gain isn't really that noticeable outside benchmarks

I'd add a network card for easy file transfers, although not much of an issue as your using a SD card.

Sound card SB16 is a good basic card and will serve you well but dos sound has many different options like external MIDI, Awe/Gus, different OPL implementations with their own pros and cons should you want to venture down that rabbit hole.

Overall though it looks like a good honest 486 system

Oh, another limitation is that the motherboard bios only supports up to a 410mb hard drive.

If you plan on upgrading the CPU I would only go with the Pentium overdrive 83mhz CPU.
Any other CPU is not worth it because they just dont have the processing power to play games in good performance.
The game play performance like in doom for example will be choppy compared to the pentium overdrive.

A 1mb video ram is fine
Sound blaster 16 with OPL3 or Media Vision PAS16 with OPL3
4x CDROM drive or faster.

Like I said.
Back in 1993 AST was selling these Bravo computer as “Multimedia” computers.
They came with
Intel 486dx-33 CPU
4mb ram
64kb cache
Proprietary 2x Sony CDROM
Media Vision PAS16 sound card
Imb of Onboard video

Thanks for all the advice!

After taking a look it seems like you are right and this system has 1mb of video memory. Like Intel said though, it's a pretty basic BIOS once I was actually looking around it.

It sounds like my next steps would be the following.

-upgrade to 64mb like in the mobo specs
-upgrade the cache to 256k
-buy a video memory upgrade if I can figure out what chip is needed - or just get an ISA video card which would be more straightforward
-solder in a new battery socket as I have some left over but would need to take the board completely out
-potentially do a cpu upgrade if I can find one for a reasonable price

I'll definitely do a build thread once I get more of this figured out.

Thanks again for all the info on this machine. I've been looking around but other than the site with the info about the motherboard and the jumpersettings I really can't seem to find much info on a lot of the Bravo LC line on the web.

As for Doom I've played through a couple levels, and while there is some slowdown when there's lots of enemies in the screen it's still fairly playable. Though I'm sure the above upgrades would help quite a bit.

If your upgrading to 256k cache for optimal performance you want 32Mb in write back mode which is the faster or the full 64mb if you set it to write though.
This is for optimal performance but does it mat THAT much of a difference? not in my opinion. personally I take the minor performance hit for that happy maxed out feeling. It's not like it suddenly makes Quake playable.

What is the video chip onboard? unless it's really crap I'd keep it. 486's don't benefit from video card upgrades as much as later systems.
VLB is what makes a 486 a 486 for some people and upgrading video cards will only gain you a couple of fps and now you'll be taking a performance hit being back on the isa bus so may not be any better off anyway.
I'd keep an eye out but not stress too much about upgrading video memory. 1Mb is fine for Dos. Windows will be able to go as high as 640x480 in high colour or 1024x768 with 256 colours, enough for basic windows usage. Not like a 486 will do much windows gaming.

As you have a SX chip you could get a DX CPU which will give you a integrated FPU. Not that this was important during 486 era for gaming. SimCity and Falcon 3.0 being the only games that took advantage of it before the Pentium era.
POD 83 is still your best bet if you want any noticeable but not ground breaking) difference.

As for doom, yeh its typical for a 486 to struggle a bit on larger levels or with plenty of action going on.
You can benchmark doom and see how your PC compares to others if you wanted
Phil's Ultimate VGA Benchmark Database Project

So for now the following parts are on order and should come in the next few weeks.

- 256k cache upgrade
-5.25" floppy drive

I was actually able to get 64mb of memory nearby but currently only have 16mb as that's all the system seems to accept for now until I deal with the cache and jumper settings. Like you said I also like seeing the 64mb in the system as well even it isn't really needed 😁

For the video chip I'm assuming the Cirrus logic one is the that deals with the video based on some googling. I've taken more pictures of the entire board as I ended up taking the whole thing out and doing the battery socket as well. I'll post the rest of the board pics once I'm finished and am doing the build thread.

I've also attached a few bench mark results from the link. Seems like it performs decently for a 486SX. As for the POD, that would be a nice to have but like you mentioned it would only be a marginal boost and the FPU really isn't needed for the era of games I could even play on this rig. If I ever do come across one I'll throw it in but doesn't seem like something worth actively seeking out.

Nice! so your onboard Video is using the CL GD4288 which is actually quite a fast card.
Phil's Computer Lab has it in a benchmark where its the 2nd fastest card, although as he mentions he is missing the top cards on the VLB
https://youtu.be/7Ha8Q_oLUr8?t=25

Compatibility is also really good. I picked up a 486 with the same chip onboard and played though the Orc campaign of Warcraft and didn't get the noise issue, which is a bonus as well 😀
https://gona.mactar.hu/DOS_TESTS_VLB/

This is shaping up to be a nice little 486 indeed, and that pic. It's a very clean system even more then your cup! 🤣

Hmm so I finally got my cache upgrade and was super excited to get it all set up but having the cache installed seems to cause a ton of issues when I actually try to boot up dos.

I did check the jumper settings and in the BIOS it can detect the 256k. However whenever I try to load into dos it always either freezes up or just resets on it's own.

My main suspicion is either that the chips I was sold were bad, or that I don't have the correct chip for my TAG chip. While I don't actually know what the TAG does, it's the only one that a 32 pin socket and separate from the rest, which leads me to believe it's more related to memory management than the other chips.

Would anyone be able to point in the general right direction?

I'm no cache expert as only upgraded my first PC last year.
Apparently plenty of fake chips exist out good chance it is due one or more been bad.
You can drop the system back to 128k and mix and match chips till you find the faulty one

Did you use the same chip for tag as you did for the rest? maybe it needs a different type, It's uncommon but does exist.
also what chips did you get I can't quite make it out, hope its the pics that are out of focus and not my eyes!