First post, by feipoa
- Rank
- l33t++
I put a 50 MHz crystal oscillator in my VLSI-based 386 motherboard and a Texas Instruments 486SXL2-50. These CPUs require software to enable the clock-doubling feature. I run cyrix.exe -cd, which sets bit 6 of CCR0 to enabled (1). You can confirm this by running cyrix.exe -d. You will see that the raw dump shows a value of 40 hex for CCR0, which translates to 1000000 in binary, so bit 6 is indeed enabled. However, chkcpu shows approx 25 Mhz as the CPU speed. The 3dbench scores before and after enabling clock-doubling are the same. Clearly the CPU isn't doubling its clock. I tried running cyrix -cd before and after enabling the L1 cache, but the 3dbench results are the same.
Has anyone had success in enabling clock-doubling on these SXL CPUs and if so how did you do it?
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