VOGONS


First post, by Baoran

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I had a bit of fun today and decided to test about slowing down my Pentium 3 1000Mhz retro pc. I am sure someone has already done this before but I still thought about sharing it with you.
First I slowed the cpu to 500Mhz in bios by slowing down the bus from 133Mhz to 66Mhz and disabled both caches and then I used throttle with command "throttle F" to maximize the slowdown. You need a chipset on motherboard to support incremental slowdown to use throttle like that.

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Basically I managed to make the original dos defender game from 1983 to be playable on a pentium 3 like mine. Defender usually requires a 4.77Mhz PC and is way too fast even on a 286. I didn't even have to use any TSR to get to this speed. Perhaps later I can find some other old games like this to test this more.

Reply 2 of 7, by Baoran

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Intel486dx33 wrote on 2020-02-21, 19:18:

What revision motherboard is it ?

Revision 1.03, but main thing is the chipset. Only via chipsets allow 6.25% increments with throttle. Other chipsets would allow only 12.5% increments which would end up being twice the speed at highest setting.

Reply 3 of 7, by Jo22

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Baoran wrote on 2020-02-21, 18:50:

Basically I managed to make the original dos defender game from 1983 to be playable on a pentium 3 like mine.
Defender usually requires a 4.77Mhz PC and is way too fast even on a 286. I didn't even have to use any TSR to get to this speed.
Perhaps later I can find some other old games like this to test this more.

Looks cool! 😎 I played Defender too on my Sharp MZ-700 when I was little.
Coincidentally, I also encountered speed issues, but I didn't know that at the time.
The game was written for the predecessor, the MZ-80K, which ran its Z80 roughly half the speed, ~2MHz.
https://www.youtube.com/channel/UCM_rzw6WcXib … ?query=defender

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 4 of 7, by Baoran

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Jo22 wrote on 2020-02-21, 20:26:
Looks cool! :cool: I played Defender too on my Sharp MZ-700 when I was little. Coincidentally, I also encountered speed issues, […]
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Baoran wrote on 2020-02-21, 18:50:

Basically I managed to make the original dos defender game from 1983 to be playable on a pentium 3 like mine.
Defender usually requires a 4.77Mhz PC and is way too fast even on a 286. I didn't even have to use any TSR to get to this speed.
Perhaps later I can find some other old games like this to test this more.

Looks cool! 😎 I played Defender too on my Sharp MZ-700 when I was little.
Coincidentally, I also encountered speed issues, but I didn't know that at the time.
The game was written for the predecessor, the MZ-80K, which ran its Z80 roughly half the speed, ~2MHz.
https://www.youtube.com/channel/UCM_rzw6WcXib … ?query=defender

Before this the last time I played defender was in mid 80s on a VIC-20 cartridge, so I can't be absolutely sure it runs at exactly correct speed. It must be close enough though because it is playable and doesn't feel too fast. It seems different compared to that sharp game that you played it on. My gravis joystick had some problems with it though because the center seemed to drift which means that the craft you are controlling eventually didn't stay still when the joystick was centered. Not sure if this was a speed issue or if it was because the joystick was probably much newer than the game itself.

Reply 5 of 7, by Revolter

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Baoran wrote on 2020-02-21, 19:33:

Only via chipsets allow 6.25% increments with throttle. Other chipsets would allow only 12.5% increments which would end up being twice the speed at highest setting.

Are you sure this is the case? Internally, throttle.exe file states that setting "F" is: "hello? is this thing on? (93.75% throttled)"

Intel chipsets are limited merely by 6.25%, topping out at 87.5%.

Last edited by Revolter on 2020-02-24, 10:38. Edited 2 times in total.

Celeron 800, 512MB, GeForce2 MX, ES1938S/DB S2, 128GB SD, Windows ME/DOS 6.22

Reply 6 of 7, by Baoran

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Revolter wrote on 2020-02-24, 10:30:
Baoran wrote on 2020-02-21, 19:33:

Only via chipsets allow 6.25% increments with throttle. Other chipsets would allow only 12.5% increments which would end up being twice the speed at highest setting.

Are you sure this is the case? Internally, throttle.exe file states that setting "F" is: "hello? is this thing on? (93.75% throttled)"

Intel chipsets are limited merely by 6.25%, topping out at 87.5%.

87.5% slowdown is twice as fast compared to 93.75% slowdown. It is comparing 1/16th speed compared to 1/8th speed.

Reply 7 of 7, by Revolter

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Baoran wrote on 2020-02-24, 10:35:

87.5% slowdown is twice as fast compared to 93.75% slowdown. It is comparing 1/16th speed compared to 1/8th speed.

The VIA setting "E" is equal to Intel setting "7" though. All the "A" through "F" levels are not present on Intel chipset boards, because there are twice as much increments on VIA chipset boards. But each even VIA level (2, 4, 6, 8, and also letters A, C and E) corresponds to Intel chipset boards' 1, 2, 3, 4, 5, 6 and 7. Each odd level (1, 3, 5, 7, and also letters B, D, F) is a VIA-specific 6.25% increment.

On a side note, could you please check if BattleZone (1983) runs fine at "E" and "F" settings on your rig? All my VIA motherboards behave badly on uppermost settings, showing erratic performance and ignoring mouse/keyboard input at random, while on i815/ICH2 motherboards everything is perfect.

Celeron 800, 512MB, GeForce2 MX, ES1938S/DB S2, 128GB SD, Windows ME/DOS 6.22