Are you using this for dos or Windows games?
It'll make for a great dos PC but many windows games would be better on a faster PC.

The CL5446 isn't a bad card for a P233MMX. It has good dos compatibility which is where you will do most of your gaming.
The SB0160 (SB Audigy) is a good card for Win9x and does have dos support, but your better off finding a ISA sound card if you can.

I always liked that case style, they were still using on PII computers.

Well I intended to use this for DOS and Windows games but I soon realized that there is too much time difference between them. I think I will revert it to DOS + WIN3.1 and ditch the whole 98 thing, or maybe use a SD2IDE and make two or three different installations (of course accepting the machine limits on what can be run or not). I have tried the W98 dos mode but I do not like it, some games are not fully compatible ( i keep getting glitches in lemmings)
So after asking the sound guys here for advice, I will remove the Audigy and install the terratec Base-1 + the SC-55st. I will live with the terrible AD1816 synthesizer until I find a better option.

Are you playing Lemmings from within windows or booting into pure dos mode?
I doubt the glitches are related to "dos 7" as it's informally known as. For the most part it behaves exactly like 6.22 with slightly better memory management and FAT 32 support.
But if your installing Win3x then agree dos 6 just feels more right

You can just disable Windows autostart and then you will start Windows 98 SE by typing "win" like you would with Windows 3.11
Win98SE will usually start despite loading DOS drivers - some more sophisticated might however interfere with startup. For that it is best to just create startup menu and have Windows as one of the options. It is useful because sometimes you e.g. cannot load emm memory driver or limit memory to 16MB, etc.

As for computer itself I have something very similar with also P166MMX. Maybe even identical - not quite sure as I don't have it at the hand to check. Ran quite fine from what I remember. I also tested it with Cyrix 6x86MX which incidentally runs at the same 2.5x66MHz = 166MHz settings. Cyrix is both faster and slower. Windows runs quite a bit better but 3D games run visibly slower. I don't think you could put anything better than Pentium MMX 233MHz. Maybe do some OC on it?