On 3/23/2012 12:27 PM, Brian wrote:
I have a Zip GSX card with the following components: 64Mhz crystal, 74LSO logic chip, 14Mhz CPU, and 32k cache memory (using two 6" RAM chips and two 3" ones). It works fine, but I want to upgrade it to 64k cache. But when I upgraded the cache to 64k (and adjusted the dips accordingly) the system doesn't turn on, just makes some beep noises). When I downgrade back to 32k it works fine. What do I need to do to get it running at 64k?
16Mhz is optimistic at best on a IIgs, especially a ROM 01 board. The Transwarp GS can do 12.5Mhz provided it has proper cooling and a beefy power supply. 10Mhz seems to be a reasonable crash free speed for my board. I tried 16Mhz on my ROM 01 and the machine crashed because the slowdown logic for bus I/O wasn't kicking in fast enough, so timings were off. I've read that the ZipGS is tougher to overclock due to the logic being in one giant PGA chip as opposed to the discrete components that TWGS is constructed of.