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CPU Upgrade Question

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Anonymous
a b D Laptop
a b à CPUs
June 3, 2005 5:08:00 AM

Archived from groups: comp.sys.laptops (More info?)

I wanted to upgrade the CPU in my laptop, which is a Toshiba 1415
(Celeron 1.8 GHz). Essentially the same computer was sold by Toshiba as
a 2415 with a Pentium 4 instead of a Celeron, and they use the same
bios. So I bought (E-Bay) the closest CPU I could find:

Celeron CPU SL6J4

Pentium 4 CPU SL6FH

These CPUs are almost identical. Same stepping (C1), same CPUID
(0F27H), same geometry (.13 micron). Basically, the only difference is
that one is a Celeron, one is a full Pentium 4.

Well, it doesn't work. When I install the P4 and turn the computer on,
all that happens is that it get a loud continuous tone from the speaker.
No boot, no post, no nothing (but it does respond to the power off
button, if you hold it down).

Now there are two possibilities:

1. I got a bad CPU

2. Although they are similar, you can't convert a 1415 to a 2415 simply
by changing the CPU.

Does anyone know any way to find out what the situation is?

By the way, chaning the CPU (which is socketed) in this model is very,
very easy. It's under the keyboard, and very little disassembly is
required.

I am also considering changing the "combo" drive (DVD player and CD
burner) to a DVD burner (Toshiba SD-R6472). It looks like a
straight-out replacement, on paper (but so did the processor swap).

More about : cpu upgrade question

June 3, 2005 5:08:01 AM

Archived from groups: comp.sys.laptops (More info?)

is the front side bus the same?

"Barry Watzman" <WatzmanNOSPAM@neo.rr.com> wrote in message
news:Q3One.16478$JX5.13007@tornado.ohiordc.rr.com...
>I wanted to upgrade the CPU in my laptop, which is a Toshiba 1415 (Celeron
>1.8 GHz). Essentially the same computer was sold by Toshiba as a 2415 with
>a Pentium 4 instead of a Celeron, and they use the same bios. So I bought
>(E-Bay) the closest CPU I could find:
>
> Celeron CPU SL6J4
>
> Pentium 4 CPU SL6FH
>
> These CPUs are almost identical. Same stepping (C1), same CPUID (0F27H),
> same geometry (.13 micron). Basically, the only difference is that one is
> a Celeron, one is a full Pentium 4.
>
> Well, it doesn't work. When I install the P4 and turn the computer on,
> all that happens is that it get a loud continuous tone from the speaker.
> No boot, no post, no nothing (but it does respond to the power off button,
> if you hold it down).
>
> Now there are two possibilities:
>
> 1. I got a bad CPU
>
> 2. Although they are similar, you can't convert a 1415 to a 2415 simply
> by changing the CPU.
>
> Does anyone know any way to find out what the situation is?
>
> By the way, chaning the CPU (which is socketed) in this model is very,
> very easy. It's under the keyboard, and very little disassembly is
> required.
>
> I am also considering changing the "combo" drive (DVD player and CD
> burner) to a DVD burner (Toshiba SD-R6472). It looks like a straight-out
> replacement, on paper (but so did the processor swap).
Anonymous
a b D Laptop
a b à CPUs
June 3, 2005 7:23:33 AM

Archived from groups: comp.sys.laptops (More info?)

Yes. The two CPUs were picked to have identical characteristics in all
regards, even same stepping and same processor ID, except that one is a
P4 and one is a celeron (surprising to me that they would therefore have
the same CPUID, but they do ... 0F27).


BigJim wrote:

> is the front side bus the same?
>
> "Barry Watzman" <WatzmanNOSPAM@neo.rr.com> wrote in message
> news:Q3One.16478$JX5.13007@tornado.ohiordc.rr.com...
>
>>I wanted to upgrade the CPU in my laptop, which is a Toshiba 1415 (Celeron
>>1.8 GHz). Essentially the same computer was sold by Toshiba as a 2415 with
>>a Pentium 4 instead of a Celeron, and they use the same bios. So I bought
>>(E-Bay) the closest CPU I could find:
>>
>>Celeron CPU SL6J4
>>
>>Pentium 4 CPU SL6FH
>>
>>These CPUs are almost identical. Same stepping (C1), same CPUID (0F27H),
>>same geometry (.13 micron). Basically, the only difference is that one is
>>a Celeron, one is a full Pentium 4.
>>
>>Well, it doesn't work. When I install the P4 and turn the computer on,
>>all that happens is that it get a loud continuous tone from the speaker.
>>No boot, no post, no nothing (but it does respond to the power off button,
>>if you hold it down).
>>
>>Now there are two possibilities:
>>
>>1. I got a bad CPU
>>
>>2. Although they are similar, you can't convert a 1415 to a 2415 simply
>>by changing the CPU.
>>
>>Does anyone know any way to find out what the situation is?
>>
>>By the way, chaning the CPU (which is socketed) in this model is very,
>>very easy. It's under the keyboard, and very little disassembly is
>>required.
>>
>>I am also considering changing the "combo" drive (DVD player and CD
>>burner) to a DVD burner (Toshiba SD-R6472). It looks like a straight-out
>>replacement, on paper (but so did the processor swap).
>
>
>
Related resources
June 3, 2005 7:31:54 AM

Archived from groups: comp.sys.laptops (More info?)

Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
: Yes. The two CPUs were picked to have identical characteristics in all
: regards, even same stepping and same processor ID, except that one is a
: P4 and one is a celeron (surprising to me that they would therefore have
: the same CPUID, but they do ... 0F27).

Same voltage?

Well, obviously you could plug the P4 into a desktop motherboard, if
you have one, to check it out to see if it's good. (What happens if
you power on the board with no CPU in it? Same effect?)

Have you looked at the data sheets for a mobile Celeron compared to a
P4?

Are you really going to get a lot of bang for the buck in this case?
The Mobile Celeron has a larger cache than the desktop Celeron, as
large as the comperable P4 in this case, no?

Andrew
----> Portland, Oregon, USA <----
*******************************************************************
----> http://www.bizave.com <---- Photo Albums and Portland Info
----> To Email me remove "MYSHOES" from email address
*******************************************************************
Anonymous
a b D Laptop
a b à CPUs
June 3, 2005 7:47:28 AM

Archived from groups: comp.sys.laptops (More info?)

The voltage of a CPU is not fixed but is controlled by the Vid pins of
the CPU, communicating to the Vcore switching power supply on the
motherboard. Even if the FSB or voltage was wrong, the system would
still work (perhaps not for long, but the result would be different than
what I saw). There are real hardware differences between a Celeron and
a P4, the P4 has "speedstep", which changes the clock frequency
(multiplier) and CPU voltage. This was a concern, but normally an
incompatability in this regard will simply cause the CPU to operate at
the "slow" speed.

I'm not sure if the laptop CPU will fit into a desktop motherboard. I
might investigate that, however.

The cache in the Celeron (256k) is half the cache in the P4 (512k) and
there are other differences. The difference in overall performance is
15% to 30%, in favor of the P4.


Andrew wrote:

> Barry Watzman <WatzmanNOSPAM@neo.rr.com> wrote:
> : Yes. The two CPUs were picked to have identical characteristics in all
> : regards, even same stepping and same processor ID, except that one is a
> : P4 and one is a celeron (surprising to me that they would therefore have
> : the same CPUID, but they do ... 0F27).
>
> Same voltage?
>
> Well, obviously you could plug the P4 into a desktop motherboard, if
> you have one, to check it out to see if it's good. (What happens if
> you power on the board with no CPU in it? Same effect?)
>
> Have you looked at the data sheets for a mobile Celeron compared to a
> P4?
>
> Are you really going to get a lot of bang for the buck in this case?
> The Mobile Celeron has a larger cache than the desktop Celeron, as
> large as the comperable P4 in this case, no?
>
> Andrew
> ----> Portland, Oregon, USA <----
> *******************************************************************
> ----> http://www.bizave.com <---- Photo Albums and Portland Info
> ----> To Email me remove "MYSHOES" from email address
> *******************************************************************
>
!