There is an DMA or other timing discrepancy between the AHA-284x(A) adapter and the VL local bus. The AHA-284x(A) adapter has been tested to run successfully on the VL Bus at speeds of up to 33 MHz. These CPUs can increase the Bus speed beyond 33 MHz. Above this 33 MHz speed, variations in motherboard, chipset or CPU design may cause our adapter to function intermittently or to fail. In some cases this problem can be resolved and we offer these suggestions:

1. The motherboard may have jumpers that govern the VL Bus speed. Be sure that the VL Bus speed jumper is set in the <="33" MHz (less than or equal to 33 MHz) position. This may also be set in the motherboard's CMOS setup.
2. In the CMOS setup, you can disable the CPU external cache, change the caching method to write-through instead of write-back. Also, Jumper J5 controls write-back cache compatibility. Try placing a jumper on this jumper block.
3. The Internal cache on some CPUs may cause this hang as well. Disabling the CPU's internal cache may help.
4. Reducing the CPU speed may be necessary to allow the AHA-284x(A) adapter to function reliably.
5. Disable the system's turbo setting during the boot-up sequence. Then re-enable the turbo setting after the system has booted.
6. Of all the various CPU chips on the market, the Intel 486DX series of CPUs seem to be the most compatible with our adapter.