A Question of Capacitors

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I’ve gotten/seen a few notes about the number of capacitors on the back of C1 stepping PIVs.

Here’s one:

I just went to one retail PC shop near my home and asked
them to show me the P4’s they had. They had only P4 2.4GHz 533Mhz.

The strange thing was that the labeling on that OEM processor was SL6DV,
which corresponds with C1 OEM chip codes, but the placement of the caps on
the downside and the amount of them was the same as in B0 chips.

Someone in our forums recently a similiar observation.

Twelve Instead of Fifteen

One of the changes made in the C1 stepping involved the PIV going from fifteen smaller capacitors on the B0 stepping chips to twelve bigger ones on the C1 stepping chips.

If you want to see a picture showing the difference, take a look at the second picture on this page. The second CPU in the picture is an original Northwood, the last one is a C1 stepping Northwood.

Twelve Arranged Differently

Now look at the second picture here. This is the back side of a 3.06. It has twelve capacitors like a PIV, but the back side is arranged more like a B0 Northwood.

What Do You Have?

If you have a C1 stepping PIV, and it’s not too much trouble, I’d like to know what sort of arrangement you have on the back of your C1 stepping CPU.

Does it have fifteen capacitors on the back like a B0 Northwood? Does it have twelve arranged like the original C1? Or does it have twelve arranged like the 3.06?

If it looks like a B0 Northwood, I would love to get a picture, front and back of it (I’d like to see the codes on the CPU, too). Please send it to me. If you can’t do a picture, please send me at least the code information and let me how you’ve done with it.

If it looks like the original C1 stepping Northwood, I’d like to know the second and third lines of code on the front of your CPU (sspec and FPO). Please send it to me and let me how you’ve done with it.

If it looks like the 3.06GHz, I would love to get a picture, front and back of it (I’d like to see the codes on the CPU, too). Please send it to me. If you can’t do a picture, please send me at least the code information and let me how you’ve done with it.

I am especially interested in Dell chips, very late model chips, and any chip that has done extraordinarily well.

I suspect you’re going to find it’s either option two or three.

Update: See this?

Dell18C1

This has a capacitor arrangement identical to a 3.06. It actually is a Dell 1.8A manufactured week 40. Not incidentally, it also overclocks to 3.5GHz.

Not to say all CPUs with this arrangement will do the same. Not to say all Dell 1.8As are like this (we already know they aren’t). Not to say you have to have this arrangement to reach 3GHz, or even reach it easily (we already know of chips with “conventional” C1 capacitor arrangements that can do this).

What this does say is that we need to look into this more, and we need everyone with C1s to help us out a bit to get a better idea about this.

Playing Detective

We have a bunch of C1s that are breaking 3GHz easily. We have a bunch that aren’t. What I’m trying to do now is see if there’s any single factor that makes a difference at least a lot of the time, and pursuing a number of leads to see if we can identify those that can from those that can’t.

A few days ago, we asked about a few other possibilities. So far, a few people have been able to break 3GHz due to the suggestions, but there’s no smoking gun so far.

This is another lead. It may or may not pan out. If we knew, there would be no need to ask. There will be others.

It may turn out that there is no one big single identifying factor. There probably are quite a few little ones; the question then becomes, “Is the only big one the fact that some C1s simply can’t cut it at 3GHz?” We’ll have to see.

I’ll tell you one thing, things are getting awfully toasty with a PIV running at close to 3GHz with what has been the standard Intel cooler. Intel itself has considerably beefed up its cooler for the 3.06GHz. I wouldn’t be at all surprised if heat wasn’t a block to higher MHz at least sometimes.

Some are suggesting that there’s something inherently wrong with the 845PE chipset as it gets around or past 166MHz, but while that can’t be ruled out, there’s quite a few more likely suspects ahead of it at the moment.

For the moment, getting a fan on the Intel northbridge couldn’t hurt.

We’ll just keep plugging away.

P.S. We also have a forum thread on this subject.

Ed

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