Steps to be continued

Annexes: some concrete cases

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Juan Herreras Rey

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To install a microprocessor

His publicity in CsH


I annex 1: to update 386 or low

It turns out to be impossible without changing the motherboard. Or it is welded to the same one, or the update would happen for finding a chip compatible with these so ancient sockets (certainly, without the "kind lever" of the sockets ZIF), which is more improbable that to find the proverbial needle in the hayrick.

Also, the yield increase changing only the mike would be insufficient for any "modern" task, therefore it would not be worth it. In these cases, the best thing is to change the whole badge or even to buy a new computer (almost better, because this way we renew the hard disk, the graphic card...). If it is much purified of money, I recommend to him the second-hand market.


I annex 2: to update 486

With these mikes the options keep on being very limited, due to his already venerable age; if despite it he wants to practise "archaeology of the hardware", first of all he will have to know if the badge can provide a voltage of 3,3 V, in addition to 5 V outstanding figures. This limited voltage is that of the mikes to 100 MHz or more (for example the AMD 486 DX4 to 120 MHz in which I wrote part of these lines), which would be most adapted to update the mike for very little money.

To know if we can use this voltage, theoretically it would be enough to look in the manual of the motherboard. I say theoretically because in numerous occasions the manual indicates that it can admit sayings chips, but in the badge the regulator of necessary voltage is missing. It happened to me; and that that I had demanded that they should put to me a badge that was admitting the above mentioned update, but in shops as Intertex (current Megaboom or Group Star) do not know about promises...

OverDrives for 486 models Pentium, DX4 and DX2

If roughly overdraft seems that empty square suspects do not exist in the badge, where a species of generally black aparatito should go, with fins and anything similar to condensers, and the manual indicates that yes he supports 3,3 V, it is time to start looking for a mike. He would recommend an AMD 486DX4 to 120 MHz (40 MHz x 3 and 3,3 V), or if not the outstanding figure (and much slower) DX4-100 (33x3 to 3,3 V), well of Intel, AMD or Cyrix.

Also there are good mikes (even better) Cyrix 5x86, to 100 MHz or more, and of course the mikes of update as Intel OverDrive or the models based in 5x86 of AMD (486 promoted that works to 133 MHz, 33x4).

The good of these mikes is that there are mikes that work to 5 V (included OverDrive DX4-100), since they have their own voltage regulator; the bad thing, to find them and his price. Intel OverDrive existed in the shape of DX4-100 "Pentium" 63 83 (in fact, it does not reach by no means a normal Pentium; 83 MHz that gives good results less than an AMD DX4 to 120 MHz).

In any case, it will find it hard to him enough to find any of these mikes, so I installed what it finds; perhaps looking for Internet... But if they ask him more than 4.000 ptas for any of them, do not bother; change the whole badge, although it is for one second-hand. Inserting a chip OverDrive in a socket ZIF of 486

To install physically 486, if it is lucky of that it is a question of a socket ZIF (with lever), the process to be continued is the habitual one; if it is a question of the most ancient socket PGA (used even with the first 486), the extraction and insertion of the mike will be realized by pure pressure, complicating the operation. To extract a mike of a socket PGA, lever does very slowly with one or several screwdrivers in the wings of the chip, changing side whenever I raised it a little (never the whole moment in the same side!). It is complicated and risked, but it is possible to do.

Do not forget to place the jumpers in the positions that correspond according to the manual of the badge, to indicate the new characteristics of the mike (badge speed, multiplier, voltage...), nor install a spendthrift and fan for any 100 MHz mike or any more.

In any case, remember that the maximum increase of yield, which is that 133 MHz or a Cyrix would give an AMD DX4 to 120  5x86 to 100 120, will only come to that of a Pentium to 75 MHz, into what if he wants an authentic jump in the yield I changed the whole motherboard.


I annex 3: to update a Pentium

If you possess one of the first Pentium, to 60 66 MHz and 5 V, the only solution that he has left is to install an OverDrive or to change the entire badge, what unless it finds a very cheap OverDrive is always preferable; originally the price of the OverDrive that was doubling the speed to 120 133 MHz was equivalent to that of a badge and mike new.

Classic Pentium

If what it has is a Pentium to 75, 90, 100..., he will need to know the options of update of the badge. It is important that it determines:

  • how is selected the speed of badge (50, 60 66 MHz);
  • how is selected the multiplier (x1, x1,5, x2...);
  • what voltages does he support (simple or double and his admissible status).

A Pentium 75 will be able to change this form for example (50x1,5) for a Pentium 133 simply selecting a speed of badge of 66 and a multiplier x2, in addition to changing the mike... or, if a good fan is obtained and he wants to risk, it can do overclocking to make for example the same Pentium 75 this to 90 MHz (60x1,5), although this can do that the chip gets damaged (apart from warming up more, hence the importance of the quality of the fan).

Bear in mind that the normal Pentium are not interchangeable "such a which" for the MMX, between other things for voltage topics, so he reads carefully the manual of his badge before trying to install one. Also it can place an OverDrive, but unless it very is lucky it will work out for him too expensive, or an AMD K5. The K5 75, 90 and 100 are formed like normal Pentium (50x1,5, 60x1,5 and 66x1,5), but the 120, 133 and 166 are more advanced, therefore to obtain an equivalent yield (a PR, yield index) to Pentium 120, 133 and 166 they need less MHz, in particular 90 (60x1,5) for PR120, 100 (66x1,5) for PR133 and 116,66 (66x1,75) for the PR166.

Also, the multipliers in the AMD K5 are fixed and internal to the chip, therefore it is necessary only to select the badge speed. The only snag of these chips is his bad unit of floating comma, which invalidates them for CAD and games in 3D (both things can be done, but if it is going to be his principal use they are not worth it), although they are perfect for office computerization. With the Cyrix 6x86 the same spends (to see table below).

And if he wants a big increase in speed and power to use applications optimized for MMX but his badge does not admit the limited voltage of these mikes, he still has left the option of the WinChip (ejem... if it finds it, it is descatalogado). This mike is completely compatible with the Pentium MMX, but with the voltage of a classic Pentium.

The installation of the chip does not change for anything of the already explained one, being very simple since the socket will be almost always of the type ZIF. In general, the biggest problem takes root in the configuration of the mike, especially in the voltages; here we present a table with the principal characteristics of the chips type Pentium and compatible:


Internal MHz

MHz it tackles



Pentium 60 and 66




5 V

Pentium 75 to 200

75 to 200



3,3 V

Pentium VRE

More unstable, they need a major voltage

3,4 to 3,6 V

Pentium MMX (P55C)

Voltage reduced for the internal nucleus (core)

2,8V I intern, 3,3V day pupil

AMD K5 PR75 / 90/100



I fix

3,3 V

AMD K5 PR120 / 133/166



I fix

3,3 V

Cyrix 6x86 (M1) P120 / 133/150/166/200




3,3 V

Cyrix 6x86L (low voltage)




2,8V I intern, 3,3V day pupil

IDT WinChip C6

180 to 240


x3/x4 (it uses x1,5 like x4)

3,3 3,52V

For more information about each of the chips, pulsate on his name in the table.


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