First post, by morgul12
Hi all,
I have a QDI 486 motherboard with SIS 471 chipset and 256KB L2 cache that has been awesome to use.. I have used all sorts of CPUs in this motherboard, including Intel 486 DX thru DX4 CPUs, AMD 486 and 5x86 CPUs, all sorts of Cyrix CPUs, and a few of those AMD 5x86 QFP overdrive-style chips such as Evergreen 586 and Kingston TurboChip. Intel 486 Overdrive DX4-100 also worked fine. Most of the time, I'm using an AMD 5x86-133, overclocked to 160 MHz. Everything is stable and works well.
However... yesterday I obtained a Pentium Overdrive 83MHz CPU... and it's been giving me trouble.
The long and the short of it is that the system will POST and I can boot into DOS if I skip config.sys/autoexec.bat (i.e. press F5). If I do a full boot, the system will hang after loading a couple of device drivers. So.. I quickly boot into DOS and try running some benchmark programs from the collection that Phil's Computer Lab assembled. Running SysInfo immediately hangs the system before giving any info. Running Doom causes a crash while loading, usually with a few lines of the letter "D". Running one of the others (Chris' 3D Benchmark, I think) results in a Page Fault error.
Disabling L2 cache immediately resolves all of these failures. All of the benchmarks run smoothly; no crashing, no hanging, and running them multiple times always results in success.
I've read about faulty cache causing such problems.. but my system has been perfectly stable with all other CPUs that I own, including those that are presumably running faster (overclocked 5x86's.. admittedly, Quake ran faster on the Pentium Overdrive even with L2 cache disabled, but the overclocked 5x86's beat the Pentium Overdrive in everything else).
I did try changing all memory timings in the BIOS to the slowest settings and then enabling L2 cache; same problem.
So... does anyone have thoughts on this? Is there, perhaps, something that might be tried besides disabling the L2 cache? Has anyone had a bad cache chip that has resulted in these symptoms (everything works perfectly for most CPUs but fails with one particular type)?
Thanks for any insight you have on this.