If it boots to DOS, check the right frequency with CHKCPU program. Old BIOSes don't have support for newer processors and usually won't properly display cpu type and speed.

kixs wrote:

If it boots to DOS, check the right frequency with CHKCPU program. Old BIOSes don't have support for newer processors and usually won't properly display cpu type and speed.

Unfortunately it hangs after the ram counter, this don't happen with the other lower cpus. I try to look for a bios update but I suspect it will be hard to find.

Looks like it is overclocking there and not stable sadly, just drop the fsb down to 25mhz and everything should be fine.

nforce4max wrote:

Looks like it is overclocking there and not stable sadly, just drop the fsb down to 25mhz and everything should be fine.

I tried at 25mhz fsb and it boot as DX4-75, pass the ram test and the hang at the summary table before loading the os. The cpu certainly works I used at the factory freq on another mobo. I think it's a cpu it don't understand how to run.

I've tried all the fsb and cpu model jumpers settings on the manual and still it can't boot the os with the only DX4-100. I suspect this cpu isn't supported by the bios version but a fast search and I can't find any update out there. A 66Mhz 486 isn't exatcly what I tried to build... I hoped for somethin more.

Set the cache and ram latency to slowest. Also set ISA bus dividers to 5 or 6 - possibly slowest. Maybe disable L1 and L2 cache altogether for testing.

There is no way a 486 boots at another FSB than the one set by the motherboard.

So your DX4 is booting at 100MHz, and either is wrongly recognized by the bios because of some other jumpers on the motherboard, or is simply taking a wrong entry in the bios table for CPU names (or is using a "placeholder" name.

To ensure compatibility with the overdrive, your motherboard should be set for a Intel 486 DX 33, and you should use the latest BIOS.
Depending on the previous CPU in the motherboard, jumpers could be set for an AMD CPU for example.
Be sure to thoroughly set every jumper for Intel DX 33 operation, write through. Also, put BIOS on safe settings for the beginning, using a working CPU.

Some update: as kixs said probably something to do with the memory and cache. I don't know why but when the DX2 had no problems with every settings and ram, I tried lowering the ram timing and disabling the l2 cache and changin the ram module and it ran! But it seems extremely slow (I am running w98 for the test by the way) when the Dx2-66 with 16Mb was faster indeed. Seem almost many module I have can't boot correctly with this cpu. W98 with the only 2x4MB of ram is a pain to test but I'll try to see what exatcly read from the os.

Without cache system runs very slow... this is to be expected. But Win98 won't help as it runs good on fast Pentiums. Try to enable L2 again with this RAM modules.

Now that it boots, try CHKCPU to verify the CPU settings.

Some updates: I get to boot it both to Win98 and Dos with the Overdrive DX4-100 not having other faster 5V cpus. It seems that the DX2 is more stable with any ram/cache bios config when the faster DX4 is more sensible to the various timings. I reduced the cache to 128Kbyte 15ns and using a good 16MB 50ns 72pin simm.
I try to get more results from the bench even if I find difficult to set a stable fast config cause with the wait states and ram config it change from being not much faster than the Dx2 to almost fast as a 133Mhz 486 (on paper).
3DBench get 58fps with the GD5429 VLB and speedsys get 33.0 cpu (the Dx2 got 37 and 21,76).
The bios definetely has something wrong with the cpu reading cause in the table it read specifically "120 Mhz" with a "generic" DX4-S.

By the way I'm impressed byt the VLB cards scores... impressive when compared to the ISA. And impressive also is the heatsink temperature of the Overdrive DX4; I added a fan onto it and still it amlost burn.

The system seems to run quiet well now. With 0 WS I get 39,38 in SpeedSys! Quake is acceptable (the timedemo dont show the fps result I don't know why) and Doom fly. CTCM get me a 44MB/S of the 16K WT cache.