PII vs PIII at the same clock speed?

spanky

Lifer
Jun 19, 2001
25,716
3
81
my situation goes like this. i have an older compaq presario 4660 computer with a PII300 cpu. i wanted to get a slightly faster cpu, but did not want to spend an arm and a leg... so i traded for a PIII450 cpu :) no when i was replacing the cpu, i did not seem to see any multiplier settings or fsb jumpers on the mobo. so i thought maybe the bios autodetects everything. so i plug in the PIII450 and boot. during the post, i notice the cpu is detected as a "pentium pro 300". when i get into windows... i run cpu-z and it is detected as a PIII450, but runs at 3.5 x 66mhz fsb. now i have several questions. since my bios does not recognize the PIII450 as a PIII cpu... does that mean my OS is not taking advantage of the SSE instructions? other then SSE... what r the other advantages of PIII of PII, assuming both cpu's r at the same clock speed? also... any chance that any of u guys know how i could get my stupid presario to recognize the PIII450 as a PIII? i already checked out compaq's website and got the latest (and only) bios update. like i said before, i did not see any multiplier or fsb jumpers on the mobo, and there r no cpu options in the cmos. i am thinking... perhaps i need to solder something onto the mobo to change the multipler and fsb? :confused:

anyway... yes i know this is a longshot, but it doesn't hurt to ask right? :)
 

RaynorWolfcastle

Diamond Member
Feb 8, 2001
8,968
16
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P3's all run at 100 MHz or 133 MHz FSB .
Your particular P3 is a katmai core which is just a PII core + SSE instructions. If you manage to somehow overclock it to 100 MHz FSB you'll have a P3 minus SSE. You'll likely have to use jumpers to do this, if at all possible.

-Ice
 

AndyHui

Administrator Emeritus<br>Elite Member<br>AT FAQ M
Oct 9, 1999
13,140
6
81
SSE is not a function of the BIOS, so the BIOS not recognising the processor should not be a real problem.

A correctly written program should query the processor for the CPUID string, and if it returns 067x or greater, SSE is available for use.

As icecool83 says, the original Katmai is essentially Deschutes core with SSE, and a few other small tweaks.
 

Budman

Lifer
Oct 9, 1999
10,980
0
0
Your old 300mhz cpu ran at 66mhz bus speed.

And the new 450mhz runs at 100mhz bus speed.

Does you board support 100mhz bus? maybe a jumper ?
 

spanky

Lifer
Jun 19, 2001
25,716
3
81
Originally posted by: Budman
Your old 300mhz cpu ran at 66mhz bus speed.

And the new 450mhz runs at 100mhz bus speed.

Does you board support 100mhz bus? maybe a jumper ?

thats what i am trying to find out. there is nothing on the mobo. everything is soldered already. i am wondering... if i can find the fsb jumpers... maybe i can solder some pins together. :p
 

Rallispec

Lifer
Jul 26, 2001
12,373
3
81
have you tried flashing the bios to a newer version? maybe a newer bios supports p3's better.
 

Boogak

Diamond Member
Feb 2, 2000
3,302
0
0
It's probably an LX chipset so it doesn't support 100 fsb speeds, I doubt you'd be able to physically hack it to run at that speed. Not only that, but your memory is most likely PC66 so it probably won't run at PC100 speeds. I would recommend getting a Celeron that runs at 66fsb as an upgrade instead of that pIII 450.
 

zephyrprime

Diamond Member
Feb 18, 2001
7,512
2
81
OS doesn't use SSE. Maybe parts of directx software emulation use it but that's about it. Also, linux's memory copy migh use it (not like it matters with such a slow memory system)
 

spanky

Lifer
Jun 19, 2001
25,716
3
81
hmm.... cpu-z says it is an lx chipset. dammit. anyway, thanx for the help guys :D

btw, i did not know the lx chipset only supported up to 66mhz fsb :eek:
 

Valinos

Banned
Jun 6, 2001
784
0
0
Hey at least you got SSE which a lot of today's programs take advantage of. Also, if you wanted to spend the money, you could get a used slot 1 PIII mobo from compgeeks.com or ebay. It'd probably cost about $30, but for about $40 more you could get a 1 GHz Duron w/ a KT133 or SiS 735 chipset and really see a big improvement. No sense in sticking with that hunk o junk as your main rig. Make it into a file server or something :D
 

KennyH

Diamond Member
Sep 16, 2000
5,904
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You might get the LX chipset to do 75Mhz FSB but that is about it without running into divider problems. :(
 

spanky

Lifer
Jun 19, 2001
25,716
3
81
No sense in sticking with that hunk o junk as your main rig.

did u just insult my main rig?! :disgust:

just kidding... i am just messing with spare parts :D
 

Valinos

Banned
Jun 6, 2001
784
0
0
lol, I thought that was your main rig and you were just a cheap bastage like a friend of mine still on a P3 450 himself. :D He's a programmer, whaddya expect...they're all wierdos (haha)

No hard feelings :p