Marcin1199 wrote on 2024-08-05, 13:22:

zwrr wrote on 2024-08-05, 12:40:

The memory speed is very slow, just like the Turbo switch is pressed. Are you using a GMB-486SPS motherboard? Where is its J5 Turbo Switch? According to the manual, 2-3 should be shorted to enable Turbo mode.

Yes, it is BMB-486SPS. According to the manual J5 should be open for P24-T, but I changed it to 2-3 and now it is a way better! Thank you for that advice!

However, benchamarks still looks similar. Any other ideas?

Oh friends, J5 and JP5 are not the same jumper, JP5 is for CPU settings while J5 controls Turbo Switch.

You've got 86MB of RAM, a Voodoo3 PCI, and a Seagate ST313021A (13GB but recognized as 8.4GB) all gathered on a Socket 3 MB with 1995 BIOS that couldn't even handle Y2K? Man, my 1995 P120 had 16MB RAM, S3 86C968 2MB (#9FX Motion 771), and 1GB HDD (Quantum Fireball); my 1999 P2-400 had 64MB RAM, Riva TNT (STB Velocity 4400), and 8.4GB HDD.

I'm still wondering how to achieve 86MB RAM with just 4 banks of SIMM modules: SIMM had to be installed in pairs, and GMB-486SPS had only four 72-pin RAM sockets with 128MB max RAM total, so two of them must be 32MB. How to add up the remaining 22MB then? And you want to launch WinXP on this build (which requires Pentium 233 minimum)? 🤔

It looks like you want to push the MB to its limits. IMHO if you've got smaller SIMM modules, an older video card (an S3 Trio would be very suitable), a smaller HDD, etc., use them to make sure your rig runs fine with reasonable performance, then add / replace them one by one with newer hardware (although I don't think WinXP would be a reasonable OS option). You might also want to test your RAM with MemTest86 or similar software to ascertain their health.

Marcin1199 wrote on 2024-08-05, 22:00:

It is very weird for me, that CPU-Z identifies my POD as 83 mhz, but in benchmark CPU Speed has such low level.

Puzzles me even more that integer is 4.33x faster on the reference whereas floating point is only 2.36x faster .. Typically on the same architecture I would expect that the difference in integer and closing point would be closely the same?

dormcat wrote on 2024-08-05, 22:19:

I'm still wondering how to achieve 86MB RAM with just 4 banks of SIMM modules: SIMM had to be installed in pairs, and GMB-486SPS had only four 72-pin RAM sockets with 128MB max RAM total, so two of them must be 32MB. How to add up the remaining 22MB then? And you want to launch WinXP on this build? 🤔

Does the Pentium Overdrive require pairs of SIMMs as the "real" Pentium does? I would imagine that when adapting the Overdrive to the 486's 32-bit bus, that requirement would have been removed as well?

H3nrik V! wrote on 2024-08-05, 22:23:

Does the Pentium Overdrive require pairs of SIMMs as the "real" Pentium does? I would imagine that when adapting the Overdrive to the 486's 32-bit bus, that requirement would have been removed as well?

No.
The original Pentium has 8 kB L1I + 8 kB L1D cache and a 64 bit external data bus.
To not make the Pentium Overdrive looking too slow its L1 cache has been doubled, but the external data bus has been adapted to 32 bit matching to its predecessors bus.

But perhaps filling the 2nd L2 cache bank may improve performance.

H3nrik V! wrote on 2024-08-05, 22:23:

Does the Pentium Overdrive require pairs of SIMMs as the "real" Pentium does? I would imagine that when adapting the Overdrive to the 486's 32-bit bus, that requirement would have been removed as well?

You're right: with four banks the combination could be "4x single-sided," "2x double-sided," or "2x single-sided + 1x double-sided." The number "86" is still kinda weird though; "84" or "96" would be much more reasonable.

And that Voodoo3 really deserves a better rig (P2/K6 or above). 😿

Useful thread (many thanks to dionb): Which is better when installing RAM: 4x8MB or 2x16MB?

zwrr wrote on 2024-08-05, 22:15:

Oh friends, J5 and JP5 are not the same jumper, JP5 is for CPU settings while J5 controls Turbo Switch. […]
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Marcin1199 wrote on 2024-08-05, 13:22:

zwrr wrote on 2024-08-05, 12:40:

The memory speed is very slow, just like the Turbo switch is pressed. Are you using a GMB-486SPS motherboard? Where is its J5 Turbo Switch? According to the manual, 2-3 should be shorted to enable Turbo mode.

Yes, it is BMB-486SPS. According to the manual J5 should be open for P24-T, but I changed it to 2-3 and now it is a way better! Thank you for that advice!

However, benchamarks still looks similar. Any other ideas?

Oh friends, J5 and JP5 are not the same jumper, JP5 is for CPU settings while J5 controls Turbo Switch.

The attachment Snipaste_2024-08-06_06-14-25.png is no longer available

The attachment Snipaste_2024-08-06_06-15-00.png is no longer available

Yes! That was a reason! Now real turbo is on 🔥 Thank you guys for solving problem and sorry for my earlier mistake with jumpers, because it could be solved earlier.

And final proof on Win XP! 💪🥳

Marcin1199 wrote on 2024-08-05, 23:10:

And final proof on Win XP! 💪🥳

Wow that's really impressive! I could only compete with running Win10 on an Atom N280. 😉

dormcat wrote on 2024-08-05, 22:39:

The number "86" is still kinda weird though; "84" or "96" would be much more reasonable.

It is 84. The BIOS shows "86016KB" which is 84*1024KB.

jmarsh wrote on 2024-08-06, 01:38:

dormcat wrote on 2024-08-05, 22:39:

The number "86" is still kinda weird though; "84" or "96" would be much more reasonable.

It is 84. The BIOS shows "86016KB" which is 84*1024KB.

My bad. 😅 Should have paid more attention to the POST screen.

What is the L2/RAM speed in Speedsys now?

Yes, I am also interested in the SpeedSys chart bottom right.

What is the RAM caching limit of the chipset in its current configuration?

Cacheable area, Standard 486
Cache ... WB ... WT
1024 kB ... 128 MB ... 256 MB
512 kB ... 64 MB ... 128 MB
256 kB ... 32 MB ... 64 MB
128 kB ... 16 MB ... 32 MB
64 kB ... 8 MB ... 16 MB

So with his 128 kB of Lvl2 Cache, most of his memory does not profit.

No, he should go with 16 MB in more banks for optimal performance.

Disruptor wrote on 2024-08-06, 20:34:

No, he should go with 16 MB in more banks for optimal performance.

I used to have stacks of 64mb simms when they became “very obsolete “

His board supports a full 256mb, with xp he might as well max it out and see how poorly it runs with everything maxed out.

Considering XP, more cache would help as would the write back setting on l2 to get as much catchable ram as possible

I send you a new benchamark

For me and beside the cacheable area, your L2 Cache and DRAM performance looks like it may be optimized to faster settings.