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Slowing a 440BX based PC

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Reply 44 of 51, by gerwin

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Farfolomew wrote:

I'm nearly tempted to purchase a cheap 400Mhz PII model with a DA0 or DA1 stepping just to test the theory I had earlier about only new steppings being locked. One of the reasons I wanted to get a 350Mhz is because the lvl2 cache chips are rated at 5ns instead of 5.5ns, and they're connected directly to the heatsink, rather than an air gap like with the 333Mhz model. It probably makes no difference, as you got yours to run fine at 400Mhz anyways, Gerwin, but I was thinking maybe there was a chance to get it to run at 450Mhz (same speed as my Celeron 300A). Then I wouldn't have to swap out CPUs if I wanted to play a really resource demanding game.

To summarize, we have these Deschutes Core Pentium II's (no celeron):

The P-II 333/66MHz and 350/100MHz, with 5.5 ns L2 cache.
The P-II 400/100MHz, with faster 5.0 ns L2 cache with a slower timing and heatsink connection.
The L2 cache is in the form of external chips which run at half the CPU speed.

The above three can potentially be found multiplier limited, at least when produced before week 34 1998, but maybe even afterwards. When multiplier limited they accept a multiplier of 2.0x and 2.5x, but disable the L2 cache at these settings. They run properly at multiplier 3.0x and up, until a certain limit which depends on the CPU type and the FSB speed. These CPU's are not too good for overclocking because their external L2 cache chips become the bottleneck.

Farfolomew wrote:

I did not mean to imply you're reckless with your personal data; just seems odd in this day and age to be sharing bank account information with total strangers over the internet. I mean, isn't that what Paypal's for afterall

No problem. I was more worried that I had to give paypal a full authorization to write off money from my bank account, some time ago 😜. Bank transfers are still very common for the more local internet trading here.

Reply 45 of 51, by gerwin

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It took some time, but some days ago I received the Engineering sample CPU. It is a Coppermine Pentium III 750/100, product number QH31ES Cpu world info.

The bad news: It does not respond properly to Multiplier setting 1.5x, 2.0x and 2.5x. With these multipliers it sets itself on a higher setting, with some odd readings in speedsys.

The good news: It accepts all the other multiplier settings I could throw at it. 3.0x to 8.0x. And the caches seem to work properly at all these settings. Attached the SpeedSys benchmark at 200Mhz ( 3.0x and 66MHz FSB).

It is nice to have this slow speed setting available, though for speed sensitive games one certainly needs additional slowdown methods. When set to its full speed, a Coppermine CPU is an all-round good performer: Fast 32-bit+16-bit, fast Integer+FPU, MMX+SSE, fast cache and reasonable power usage.

PS. my Aopen mainboard detects the 100MHz bus support and won't let me choose 66MHz in the bios. So that can also be an obstacle in slowing down similar systems.

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    QH31ES SpeedSys benchmark at 200Mhz (3.0x and 66MHz FSB).
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Reply 47 of 51, by gerwin

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Sorry, which link? 😕

Another thing: Although coppermine CPU's are found with 256kB L2 cache, until the release of the Tualatin-S versions with 512kB. The seller of the QH31ES stated it to have 512kB L2 cache, and CPU world also shows an image of a QH31ES mentioning 512kB L2? On the other hand Speedsys and CPU-Z detect 256kB on mine. I am afraid it just doesn't have the extra cache.

Edit: the seller assured me the CPU showed 512kB L2 when using it on his Abit BH6 mainboard...

Last edited by gerwin on 2009-03-29, 12:09. Edited 1 time in total.

Reply 49 of 51, by gerwin

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Yes, I had already read that topic. 😀 And coincidentally done the same thing some weeks ago, as written here. But for now I (temporarely?) removed the Tualatin and put in the Unlocked CPU.

Reply 51 of 51, by Tetrium

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Link to the other P2 unlock thread (posted for conveniance, so I don't have to google it every time I need it 😜 ).
Which Pentium IIs can be underclocked?

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