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Faster CPU adapters/converters to socket7 ?

T

technoid

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Dec 8, 2011
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Hi,
Were there any adapters for later/faster non-socket 7 CPU's to use on socket 7 (Pentium I) motherboards? I am talking about "later" CPU's such as the Pentium III FC-PGA formfactor, which would only work in a socket 370. I have older adapters such as the Evergreen Rev-to-486(286to486) and Evergreen 486-to-586(AMD). Currently the fastest socket 7 system I have is an AMD K6-III+ 450 overclocked to 600MHz in a DFI supersocket7 motherboard (using only heatsink-fan, no supercooling necessary), and also a K6-2 550 (or 500, I don't remember) underclocked to 450 in an old Abit AX5 socket7.

Anyway, it would be nice to have a 1.0GHz Pentium III actually running in a socket7. But If there were/are no such adapters made by companies, then modifications (mods) done by users would also be nice information to look at. Thanks.
 
Does not exist. The best you can put on a Socket 5/7 system are Super7 chips (Cyrix MII, AMD K6+), and that requires a powerleap or evergreen adapter in most cases.

The Pentium Overdrive was the last CPU upgrade which allowed you to use a next generation CPU (Pentium) in a previous generation (486) board. It was extremely flawed, and the limitations of the 486 bus really held it back.

If it were possible to build in an adapter to put a PIII on an original Penitum bus, it would be ridiculously complex, expensive and probably slow, which is why it was never attempted.
 
You have about the fastest chips for Socket 7 and Super Socket 7. You might be able to track down a 600 MHz AMD K6 variant which could conceivably be overclocked closer to 800 MHz. There were slokets putting Socket 370 chips into Slot 1 and also Socket adapters for Pentium IV Socket 478 into Socket 423. Supposedly, Powerleap had worked on a Socket 370 to Socket 7 adapter but that was going to peak at 433 MHz Celerons. Not released to my knowledge and probably would have cost more than the budget Socket 370 motherboards.
 
I do recall some company coming out with Celeron-based accelerator cards that plugged into a PCI slot... maybe it was Evergreen?

They were basically single board computers that used some software trickery to override the CPU/RAM/etc. on the motherboard. But they cost as much as a S370/Slot1 CPU + mobo, didn't perform as well, and they weren't particularly stable. So as you might guess, they never really gained much popularity.
 
Don't forget that a lot of the speed rests in the FSB speed. IIRC, the best that a plain S7 could do was 33MHz. Some of the SS7 boards could do better.
 
The 33mhz bus was from the 386/486 era. Socket 5/7 generally used a 66mhz FSB speed (or 50/60mhz in some cases), going up to 100mhz on Super7.
 
Old Thrashbarg said:
The 33mhz bus was from the 386/486 era. Socket 5/7 generally used a 66mhz FSB speed (or 50/60mhz in some cases), going up to 100mhz on Super7.
Click to expand...

Yup, you're righ, but my point--you're not getting the 100MHz FSB with a plain S7 board. i have an Amptron 8600 board that claims that it can to to 75MHz FSB, but I've never gotten it to operate reliably with a 200MHz MMX CPU.
 
Yes, but then again it is an Amptron board. PCchips wasn't exactly known for quality.

Some socket7 boards could handle 75 and 83MHz relatively well, but you had to have good RAM (PC100 should do it) and PCI cards that could handle things being run out of spec.

I have an Asus VX97 that happily runs a K6 2+ 500 at 6x75 (450MHz).

You might be able to track down a 600 MHz AMD K6 variant which could conceivably be overclocked closer to 800 MHz.
Click to expand...

Wasn't 600MHz generally considered to be the limit for K6+ chips? Why do you think 800MHz might be possible?
 
I suppose I could give it a try on an Intel AN430TX board that I have, but I suspect that I would not see much real improvement over the P1 233 MMX already plugged in. My experience with adapters has been very disappointing. Upgrading Slot 1 P2 board with Powerleap slocket running a 1.4Gz Celeron comes nowhere close (real world) to a real P3 board with a 1GHz CPU (same 100MHz FSB). I think that there's a lot more to the mix than just the CPU.
 
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What's your motivation behind this? If it's to get a very fast CPU in a system with an ISA bus to run vintage cards, you might look at industrial motherboards such as IBASE MB700 or MB800.
 
The Powerleap adapter I bought with a 1.2GHz Celeron Tualatin CPU was completely unstable in my BX system board. Supposedly the first batch were rather buggy but later ones were okay.

That's an interesting observation about the Celeron 1.4 upgrade vs true PIII 1GHz. Where was the bottleneck? In CPU or memory performance?

However, I did have pretty good luck with K6+ chips in HX, VX and TX boards, especially if you can patch the BIOS. Moving the L2 cache from the motherboard to the CPU die gives tremendous performance improvement and ability to get around chipset caching limitations. If you socket 7 board supports low enough voltages, a powerleap or evergreen adapter isn't even required.
 
That's a tough one--both motherboards being compared used the 440BX chipset and both use a PC100 memory. The issue could be with the Powerleap adapter or maybe with the BIOS. All I've noticed is that the one with the Slotket is very noticeably slower. Fortunately for me, it doesn't matter too much as the system is rarely used.
 
I'm not as familiar with PII/PIII computers as I am with older stuff, but it sounds like it could be a BIOS incompatibility. Perhaps one of the caches has been automatically disabled? My memory is not good, but I do know that some motherboards do things like that when an unrecognised CPU is inserted.
 
The test machine under consideration was a HP Vectra minitower. Since HP rolls most of their own BIOSes, it's not really something to dig into. I have a Compaq Deskpro EN P2/P3 box of about the same vintage. There, I just modded a cheap slocket to accept a Celeron 1.2 and it did seem to be a substantial improvement over the original 600MHz Coppermine Slot 1. Nice design--you have practically the whole motherboard open to access--the expansion slots are on a separate board on a slide that pulls out. But the thing is heavy
 
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