I got a replacement motherboard for my 486 since the last one I had was flaky. It's another V4S471. I installed the hacked BIOS to replace the onboard WinBIOS. I've got an Am5x86 running at 4x40MHz, 128MB of RAM in the board and 256K of 15ns cache. (I bought a bunch of 611024 chips on eBay but they were dead, as it turns out.)

The motherboard detects the cache but it doesn't seem to be working properly. According to CACHECHK, only the 21st megabyte of RAM is being cached by the L2. Access speeds are the same for all RAM except inside the 21st megabyte - 7uS/KB up to 16KB, 33uS/KB up to 4096KB. The 21st megabyte reads like it's being L2 cached, with faster speeds up to 256KB access blocks before returning to 33uS/KB.

I checked the SiS471 configuration registers in the datasheet with DEBUG.COM and all of DRAM is set to be cacheable. I checked the SRAM ICs in my TL866 and they all read good. The jumpers are set properly for 32Kx8. L1 and L2 is set for write-back.