I'm about to perform some tests on a hybrid 3/486 motherboard that I recently acquired.
However, my previous board (that sadly died a couple of years ago) didn't want to work with my S3 805 VLB graphics card.
As I recall, some users have reported faster graphics performance, but I think the 386 CPU will likely hamper overall performance.
I'm planning on running a couple of benchmarks with a 486DLC-40 and a 486DX-33 on the same board that I have to see how these two CPU's stack up against each other (both with ISA and VLB graphics cards). A 386, in my opinion, is just too slow and no L1 cache further limits performance.
I'll post my results soon.