P55C @ 300 is pretty sweet. 100x3 really clears up the 'ol bus bottleneck that's for sure.

sliderider wrote:

That was probably the best overclock I ever did to a CPU percentage wise.

Mine was a Core 2 Duo E6300 that went from 1.86 GHz to 3.2 GHz on stock voltage. Hells yes. 72% overclock. 😉[/list]

retro games 100 wrote:

5u3, I notice that you have set your Asus P5A 1.06 board to use an I/O voltage of 3.8V. Please can you tell me how this was don […]
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5u3, I notice that you have set your Asus P5A 1.06 board to use an I/O voltage of 3.8V. Please can you tell me how this was done? To the south of the mobo's VIO1 jumper, there appears to be another similar looking jumper called VIO0. Currently, it has no jumper on its 3 pins. I set both VIO1 and VIO0 jumpers to the 2-3 setting, and noticed inside the BIOS hardware voltage area, that the 3.3V setting had a value of 4V! That's a bit too high for my liking. What is the VIO1 and VIO0 jumper configuration, for an I/O of 3.8V? I have read the manual, and it doesn't even state that jumper VIO0 exists! Thanks a lot.

Give it a try like this. Remove jumper from VIO1 and put it in VIO0 1-2 for 3.8V and 2-3 for 4V.

4V...that's insane!

Thanks a lot for the Asus P5A voltage information. I have done the following, to this 1.06 revision board, with a P-233-MMX CPU installed: Removed the shunt on the VIO1 jumper, and also I have put a shunt on to pins 1-2 of the VIO0 jumper. I have also configured the mobo's multiplier jumpers to 3x, and the mobo's FSB jumpers to 100 FSB, and the CPU's voltage to 3.3V.

If I examine the readings inside the BIOS hardware area, the 3.3V reading says 3.6V. I was expecting 3.8V. Also, the +12 volt reading seems very high - it says about 12.9. I wonder why this is high? Question: when I look at these 3.3 and 12 voltage values inside the BIOS hardware area, what are these two voltage "lines" for, exactly?

However, all is well with the system, using the jumper configuration outlined above. I can boot in to Windows 98, and run various benchmarks. Previously, I tried with a CPU voltage of 3.2V, and I also had the VIO1 jumper set to pins 2-3, which means 3.6V. I could not get to the Windows 98 desktop with that configuration.

Edit: I'm wondering if an IO voltage of 3.8V can be achieved by setting the jumper configuration like this:

VIO1 o-- (pins 2-3 = 3.6V)
VIO0 --o (pins 1-2 = add a bit more voltage on to the 3.6V value above?)

In other words, set the "official" VIO1 jumper to the 2-3 pins 3.6V setting, and also set the "unofficial" VIO0 jumper setting to "notch one", which will add a bit more voltage on to the 3.6V setting. Previously, I tried the following, and the 3.3V reading inside the BIOS hardware area said 4V.

VIO1 o--
VIO0 o--

swaaye wrote:

sliderider wrote:

That was probably the best overclock I ever did to a CPU percentage wise.

Mine was a Core 2 Duo E6300 that went from 1.86 GHz to 3.2 GHz on stock voltage. Hells yes. 72% overclock. 😉[/list]

Intel SX-33 OC'd to 66 MHz. 100% overclock! Stock voltage. 😉

swaaye wrote:

P55C @ 300 is pretty sweet. 100x3 really clears up the 'ol bus bottleneck that's for sure.

What do you think, is there any chance that a voodoo2 would run at a decent framerate on a system like that? I'm wondering because I have 2 voodoo2s in SLI on my pentium 3 1GHz, along with a geforce2MX, and the latter is way faster than the voodoos. I just keep the voodoos just for 3dfx games(which I don't have too many yet, I have to admit), and would be convenient to "move" them to the Pentium mmx pc if they would work on that...

retro games 100 wrote:

Question: when I look at these 3.3 and 12 voltage values inside the BIOS hardware area, what are these two voltage "lines" for, exactly?

These are voltage readings of your PSU output. As per ATX specification, the voltages should be within 5% of the nominal value. For example, the reading for the 12V line should be between 11.4V and 12.6V.
Take these readings with a grain of salt though. The hardware monitor chips are not very accurate and the sampling rate is rather low, while the voltage continuously changes with the system load.

retro games 100 wrote:

I'm wondering if an IO voltage of 3.8V can be achieved by setting the jumper configuration like this:

VIO1 o-- (pins 2-3 = 3.6V)
VIO0 --o (pins 1-2 = add a bit more voltage on to the 3.6V value above?)

Yes, AFAIR it worked like that. The "3.8V" is a bit arbitrary though, that's just what I read from the BIOS hardware monitoring screen.

Thanks very much for the info. I now have this OC'd system stable, running 3DMark 99 Max in Windows 98. That's a good test, because previously the system appeared to be stable, but when I ran this 3D test it rebooted the machine. I am now using these settings: CPU voltage jumpers are set to 3.4V. It was on 3.3V. The IO voltage is set to -

VIO1 ooo (at the moment, there's no shunt present on any of these 3 pins)
VIO0 --o (shunt on pins 1 & 2)

The BIOS hardware area tells me that the 3.3V reading is 4V. I can't seem to get a value of 3.8V for the +3.3V setting. I've tried a few combinations of jumper settings, with and without a shunt on the VIO1 jumpers.

Markk wrote:

swaaye wrote:

P55C @ 300 is pretty sweet. 100x3 really clears up the 'ol bus bottleneck that's for sure.

What do you think, is there any chance that a voodoo2 would run at a decent framerate on a system like that? I'm wondering because I have 2 voodoo2s in SLI on my pentium 3 1GHz, along with a geforce2MX, and the latter is way faster than the voodoos. I just keep the voodoos just for 3dfx games(which I don't have too many yet, I have to admit), and would be convenient to "move" them to the Pentium mmx pc if they would work on that...

I think SLI is overkill for the mmx, even at 300Mhz.

I tried that P-233-MMX multiplier unlock "trick" again. It didn't work. I tried bridging pins Y33 and W33, and also Y33 and X34, but neither worked.

Never mind. I'm going to have a voodoo 1 instead. It's going to be fine.
btw, I've just connected it to internet by sharing the wifi connection of my laptop through the lan port, and it feels great to be posting on vogons on that old Pentium PC!

Just wanted to add some of my results I got while playing around with the 266 Tillamook I recieved recently.

Unfortunately the CPU will only work if I disable the L2 cache, which has a massive impact on the overall performance.
More Datails about that here: Re: Tillamook (in case you have a solution)

Fortunately, the CPU can be overclocked to crazy levels and the speed is so high, that the loss of the L2 cash is starting to diminish. Not by much, though.

Well, here are the specs:
The CPU runs at 440MHz. 110MHz FSB and (locked) mutliplier of 4.

Remember: All tests were run with the L2 cache DISABLED!
So if you want to compare them, run tests with your systems L2 (external) cache off to see the relative performance gain.

The board reports the CPU as a "Talimook" which is pretty hilarious.

Speedsys:

Sorry for the subpar image quality, but I just took some quick shots with my VGA grabber.
In case the values are hard to read:
Overall Score: 332.58 (between K6-2 266 and PII 300)
Memory Bandwidth: 330,42MB/s
L1 Cache Speed: 794,51MB/s
L2 Cache Speed: none 🙁
Memory throughput: 209,90MB/s

PCPBench

Final Score: 40,8FPS
Vesa Modus 100 @640x400x8 LFB

Quake 1.06 Demo1

75,0FPS

Especially Quake makes the lack of L2 cache quite obvious.
5u3 got 70,6FPS with a 300MHz P55C and L2 cache enabled.
That's just a 6% increase in performance but almost 50% more clock speed. Damn you L2 cache!

Now, imagine the results if someone figured out how to make the L2 cache available again. I'm not sure how high the performance increase would be, but I think applications like Quake would get a considerable performance boost.

FYI: The CPU cooler isn't even close to getting hot, even after a prolonged benchmark session. The system is benchmark stable even in Win98SE. So far only one application doesn't like the 440MHz and will refuse to work with anything above 420MHz.

Some applications get a significant performance boost from the increased clock speed (like the speedsys overall score), while others still suffer from the lack of L2 cache.
Shiny Benchmark is one example.
P55C Desktop at 100x2.5 will get a score of 114 in DOS.
The Tillamook (P55C Mobile) barely gets a score above 100 with the FSB set to 105 (420MHz) and the score is equal at best with 440MHz (113 Points).

Even though the results are sometimes far from spectacular, it still shows the enormous potential of the Tillamook. Unfortunately nobody has been able to run the CPU with the L2 cache enabled.

prophase_j wrote:

So from there, I contemplated strapping a Pentium Pro to a BX with one of those "slot-ket"s..

I'm guessing nobody picked up on this when it was originally posted. Was there such a thing as a slocket adapter that let you mount a Pentium Pro on it? I've never heard of one before.

Yes, it's out there. Never seen one in the flesh though.

And about Tillamook, has anyone tried it yet in a 430TX board?

Here is an image of a Socket 8 slocket adapter.
Slotket From Wikipedia

I still want to see how the Tillamook compares to the Celeron 300A at 450mhz. Which should be faster?

I think even with L2 cache enabled, the Tillamook would lose, because the celeron has got the better architecture and memory throughput&bandwidth.

Against a Covington Celeron, it might have a chance, but only with L2 cache enabled and in certain applications.

If you take a look at the speedsys CPU score, the Tillamook isn't quite on par with the PII 300. As far as I know this score doesn't take any caching etc. into account. A Covington Celeron 266 will have a higher score than a PentiumII 233, even though the latter will wipe the floor with the Celeron quite easily. But the clock speed is higher and the architecture is the same, so the Celeron gets ahead.

The 266 Covington has a score of 305-310, which isn't that far from the 440MHz Tillamook, scoring 330 points. I might be wrong about the rating not factoring the L2 cache speed, but I think just raw processing power counts in this case, so the L2 cache won't help the Tillamook here.

Of course the Tillamook will get a huge boost in other applications with the L2 cache enabled, but I still think it's no match for a Celeron or PII at the same clock speed.

But getting an answer to your question shouldn't be that hard. Getting a P55C Desktop (with L2 cache *g*) to run at 300Mhz is absolutely doable, so that could be compared to the Celeron300A at stock speed. I think the Mendocino Celeron would win, even with the lower FSB. The P55C might give a cacheless Covington a run for its money, but with L2 enabled the P6 architecture is quite good.

In my 133mhz Challenge thread I ran a PPro, PII and PMMX. See sig. Results include Speedsys and Quake. This was a performance per clock comparison.

Alright, I'm digging this thread out again, because I did a little experiment with a bunch of CPUs I got.

I collected six 233MMX CPUs to see how big the differences in the required VCore settings were when trying to achieve 300MHz.
Well, I had seven, but one was DOA 🙁

There are a few extra CPUs here. Two 200MHz P55C, one 233MHz which seems to be defective and the 266MHz Tillamook I tested earlier.
(click for larger version)

While I expected some variation in the results, I wasn't quite ready for the huge differences in CPU quality I got.

I used this system as a base for the whole experiment:
Board: DFI P5BV3+. An excellent Super7 board, but the FSB only goes up to 100MHz and the highest multiplier is 3.5
I used quality SDRAM at the most insane performance settings
The GPUs used are a Matrox Mystique and a Voodoo1
OS was DOS with Win98SE
The cooler I used is a full copper low profile So754 cooler with arctic ceramique thermal paste.

DOS Benchmarks used:
Speedsys
Quake1 (demo1)
PCPlayer Benchmark
3DBench
Shiny Benchmark (perf_dos)

In Windows I just ran a quick round of the "four" benchmark in Quake3 Arena.

If a CPU posted, I could usually run all benchmarks in DOS except for Quake1. Quake1 usually took an .1 or .2 VCore increment. I've found the IO-Volt setting to have a very small effect on the overall stability, so I usually left it at 3.3V.
Even if the Quake1 benchmark finished, Windows was another hurdle. It often took another .1 or .2 volts to get a stable desktop and sometimes an additional .1 volt to get the Q3A benchmark to run without errors.

I tested various settings and ran benchmarks for each of them.
250MHz @3x83
250MHz @2.5x100
266MHz @3.5x75
285MHz @3x95
290MHz @3.5x83
300MHz @3x100

I quickly realized that the 83MHz FSB had some problems as the benchmark results were terrible and even the 290MHz was slower than the 266 @3.5x75.
I also couldn't boot into Windows with the 75MHz FSB, no matter what the multiplier and vcore setting was. I suspect it's a problem with the PCI raid controller I had installed since the 75MHz FSB reduces the PCI Bus speed to 30MHz. Just a theory.

Because every CPU was able to run at 250 or 266MHz without any problems and the 83Mhz FSB didn't offer reasonable performance I just tested the 285 @3x95 and 300 @3x100 settings on all CPUs for the required voltage.

Btw: The speedsys CPU score doesn't really tell you anything about the system performance in games.

Alright, first the benchmarks:

FSB is King! The P55C runs perfect @100MHz FSB and the boost from the higher FSB is much higher than a few extra MHz.
Look at the difference between 250MHz @2.5x100 and 266MHz @3.5x75.
Q3A isn't really a benchmark score you could compare, as the game runs at ultra low settings. It's just for testing the stability under Win98.

Now, let's get to the interesting part, the VCore settings.
I always started with the 3x95MHz setting at 2.8V, tried to see if it posted and if it didn't, I increased the VCore by 0.1V until it did. After the CPU posted I could usually run all benchmarks except for quake, which took another 0.1V. As mentioned before, getting Windows stable often took another 0.1 or 0.2V.
Most CPUs can easily reach 285MHz with the 95MHz FSB. If your P55C can't get to 300MHz and your board has both the 95 and 83MHz FSB available, go for the 285MHz @3x95 instead of 290MHz @3.5x83. It's 5MHz less, but it's still faster due to the higher FSB.
I often didn't have to fiddle around with the VCore too much, as I quickly reached a stable Windows.

Continuing with 300MHz, the picture changed. Getting the extra 15MHz often required a huge investment in extra VCore and even then some CPUs didn't reach a stable desktop. Since my board only offered 3.5V, I had to stop there.

Here's the chart:

For the CPU Model I just took the last digits of the number above the copyright so I was able to distinguish them from one another.
As you can see, there are really REALLY big differences, even at 285MHz. Two CPUs were able to run 285MHz with the default VCore, which really impressed me. The last CPU didn't even get an error free Windows desktop, although it was stable.
The 300MHz data is the most fascinating one. Two CPUs immediately crashed, even at the highest VCore setting. I suspect the first CPU would run with 3,7V, but the last one is just hopeless. You'd have to fry it with more than 4V to get a stable Windows desktop.

Now, two CPUs stand out. They both ran 285MHz with the default 2.8V setting and required REALLY low settings for 300MHz. One ran with 3.3V, which is pretty low compared to other CPUs in this thread.
But the other (fifth in the chart) is just insane. I couldn't believe it and had to check the jumper settings three times, but that monster ran @300MHz with the default VCore of 2.8V! I'm not joking!

I'm pretty sure I could run this bad boy at 350MHz with this board, but I honestly don't want to ruin the CPU by putting too much power through it.

The holy grail of P55C CPUs? (click for larger version)

I have made one observation which might be useful, but it might just as well be a coincidence, because I didn't have a lot of CPUs to test.
Most P55C CPUs have "MALAY" printed on the back, but both of the "high performers" had "A4" printed there instead.

So there you have it.
For high performance, get the highest FSB possible, even if the speedsys CPU score suggests lower performance due to less overall MHz.
The quality of the 233MHz P55C CPUs varies greatly. I'd say theres as much as 1V difference (or more) to get CPUs running at 300MHz.
I got 3 out of 6 CPUs to 300MHz with a stable Windows desktop and Q3A benchmark.
One was close (almost stable), one would probably just need an extra .2V and one is utterly hopeless.
And 1 or 2 of the tested CPUs have the potential to go to 333MHz or even 350MHz at "reasonable" VCore settings.

Oh and if you try to get to 300MHz you should use quality components:
The mainboard is probably the most important piece. Make sure it's got a divider to keep the AGP/PCI bus at 33MHz (or slightly above/below that). Older boards don't offer this feature.
Check for a high FSB. It'll give you higher performance at lower clock speeds and it ensures L2 cache stability.
Get a board with SDRAM support and quality SDRAM. If you have 133MHz DIMMs that are detected by the mainboard, you can usually run them at the absolute fastest settings possible. The older PS/2 EDO SIMMs and even slower SDRAM DIMMS might cause trouble when running the system with a high FSB.

Now, I'd really like to confirm my theory about the MALAY/A4 233MHz P55Cs. Maybe I'll buy some more CPUs, but it's getting somewhat expensive. 😉

Now, if you have any questions or would like other tests or benchmarks to be performed, let me know.
I'll probably try the 3rd CPU in the chart @3.5x95 and 3.5x100, but I'm not going to harm the one in the photo above, it's just too precious 😉

IIRC feipoa wanted some Quake2 benchmarks. Which settings and demo should I use to have results you can compare to yours?

http://www.ebay.com/itm/Intel-Pentium-233-MMX … =item3cb25bdd91
More than 10 available... 😎