First post, by flamingpentium
I'm in the middle of a 486 build and I've hit a problem I'm hoping someone might be able to help with. While the system seems to be working fine, all CPU speed tests seem to be well below expected - at least going off the scales provided:
Landmark: 52.28Mhz FPU: 209Mhz
Norton sysinfo: 16.3 which seems to be about half the speed of a 386DX-33
speedsys: 9.35 - which seems to be about 386DX-40 on the scale.
All above programs as well as CHKCPU and MSD all correctly identify the CPU as a DX2-66
MB: 486 OPTI PAT48PG - 0.30 (manual can be found here https://manuals.plus/m/0b5246beaedf38f5916819 … a2e6bbd452c36d0
CPU is a 486DX2-66 intel overdrive version
Bus speed: 33Mhz checked on jumper and through software
Memory: 16MB (2x8MB SIMMS)
I/O: Winbond VLB
Vid: CL-GD5429 VLB
HDD: CF Card
PSU: AT (CWT-200) I assume its 200W
Sound: none installed yet.
OS: msdos 6.22 - only himem.sys and ansi.sys running so CPU is in real mode.
Internal CMOS battery is removed and disabled and using external battery header (3xAA)
My first thought was possibly a faulty cache issue. BIOS shows both internal and external cache as enabled and the MB shows 128K cache on boot but CACHECHK does throw up a "This machine does not seem to have any cache" message but then shows a "Cache ENABLED" message against the CPU - which it correctly detects. Turning off cache in bios does not seem to do anything to the benchmark numbers other than for BIOS to say there is no cache in the pre-OS boot message.
Not sure where to go from here. Any help greatly appreciated.