# Upgrading Pentium 4 CPU on HP/ASUS PTGD1-LA (Grouper-UL8E) Motherboard



## Roadster (Nov 21, 2007)

I'm interested in upgrading the CPU on my wife's desktop computer, which is an HP Pavilion a747c with a product number PJ514AA (circa 2004/05). This computer has an OEM-spec motherboard (ASUS model: PTGD1-LA; HP/Compaq name: Grouper-UL8E).

Specs for the computer and motherboard are listed on the following URLs:

Computer: http://h10025.www1.hp.com/ewfrf/wc/...en&cc=us&dlc=en&os=228&product=435561&lang=en
Motherboard: http://h10025.www1.hp.com/ewfrf/wc/document?docname=c00196251&lc=en&cc=us&dlc=&product=426755

According to the spec sheets, the base CPU is an Intel Pentium 4 520 (2.8 GHz), 800 MHz front side bus, Socket 775, Hyper Threading technology, and the motherboard supports Intel Pentium 4 HT processors that fit Socket LGA775 up to 3.4 GHz.

I've found a couple of potential upgrade options for the 3.4 GHz speed, but one of the options (Pentium 4 551, $286) is much more expensive than the other (Pentium 4 640, Prescott core, $100)...

http://www.xpcgear.com/pentium551.html
http://www.xpcgear.com/pentium650.html

The only difference between the two processors appears to be the amount of L2 cache. For some reason, the 551 chip has only 1 MB of L2 cache, but is almost three times as expensive as the 640 chip with 2 MB of L2 cache. (My current CPU, the 520 chip, has only 1 MB of L2 cache.)

So here are my questions:

1) Will both of these chips work as an upgrade on this particular motherboard?

2) If so, which one would perform better? 

I'm tempted to go with the 650 chip (2MB L2 cache @ only $100), assuming bigger is usually better, especially since it's cheaper, but I want to make sure that this CPU is actually compatible with my system.

TIA for your feedback.


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## twajetmech (Jul 1, 2004)

Hello and welcome to the TSF. According to the specs you listed it should support either cpu, however the 650 is a slightly cooler runing cpu than the 551 and the 650 will support a 64bit OS while the 551 will not. But, you may need a bios update from HP to support the 6XX cpu's and I'm not sure if HP ever bothered to update that far ahead...In reality however there is no major performance gains going from a 520 to a 551 or 650 (maybe 5% or so) I'd say you're probably better off adding more memory by replacing the 2 X 256 modules you have now with 2 X 1Gb from Crucial, Corsair or Mushkin (use their memory advisors for compatible memory)


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## Roadster (Nov 21, 2007)

Thanks for the quick reply.

I am in the process of upgrading the RAM to 3 GB as we speak, so I'm covered on that front.

HP released a motherboard BIOS upgrade back in May 2006 (v3.28)...

http://h10025.www1.hp.com/ewfrf/wc/softwareList?dlc=en&lc=en&product=435561&lang=en&cc=us&os=228

... addressing the following issues...



> Release Date: 2006-05-10 Version: 3.28
> 
> Description
> 
> ...


Do you know if Intel released the 650 processor prior to May 2006?

BTW, why can I only expect a 5% performance gain when going from 2.8 GHz to 3.4 GHz? (3.4 / 2.8 = 121%, so I thought I might get a more noticeable improvement.)

FWIW, I'm installing a new graphics card, too (EVGA GeForce 8600 GT), which I will be using to drive a HD monitor via the DVI port. That's why I'm thinking about upgrading the CPU in addition to the RAM.


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## twajetmech (Jul 1, 2004)

The 650 was released in 2005, so that should be okay. reviews of the 551 and 650 don't show more than a 5% increase in peformance over a 520, what the newer cpu's offered was lower voltage requirements and cooler running, along with (on some cpu's) 64bit OS support, they are all essentially the same cpu's just refreshed a bit as time went by. When you update the ram, be sure to add the memory in matched pairs since your mobo supports dual channel memory, thus the reccomendation to remove the 2X256 and add 2 X 1Gb. Since the version of XP you are running is a 32bit OS you can't take advantage of more than 3.25-3,5 Gb if memory (its an OS limitation) and you may encounter instability with more than 2Gb . To install a 8600GT make sure your psu is up to the task, standard HP computers come with very poor psu's and are typically woefully underpowered for any major upgrades other than an additional hdd or two. (yours is a 300W unit, not enough imho) Also with a mATX mobo be sure that you have the room in the case for the card.


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## Roadster (Nov 21, 2007)

twajetmech said:


> The 650 was released in 2005, so that should be okay. reviews of the 551 and 650 don't show more than a 5% increase in peformance over a 520, what the newer cpu's offered was lower voltage requirements and cooler running, along with (on some cpu's) 64bit OS support, they are all essentially the same cpu's just refreshed a bit as time went by. When you update the ram, be sure to add the memory in matched pairs since your mobo supports dual channel memory, thus the reccomendation to remove the 2X256 and add 2 X 1Gb. Since the version of XP you are running is a 32bit OS you can't take advantage of more than 3.25-3,5 Gb if memory (its an OS limitation) and you may encounter instability with more than 2Gb . To install a 8600GT make sure your psu is up to the task, standard HP computers come with very poor psu's and are typically woefully underpowered for any major upgrades other than an additional hdd or two. (yours is a 300W unit, not enough imho) Also with a mATX mobo be sure that you have the room in the case for the card.


Thanks for the additional info! ray:

I bought a new 400W PSU for $45, and I plan to install that with the new PCI-e graphics card. I also verified that there is sufficient room for the card in the PCI-e slot on the mobo inside the case.

I was aware of the 32bit OS limitation, so that's why I was only going to upgrade to 3 MB, instead of 4, and I had discounted the benefits of running in dual-channel mode, which I have heard are fairly negligible (similar to your CPU comparison). However, so far, I have only ordered two of the 1 GB RAM cards, and I haven't ordered the 3rd yet. I may just stick with 2 GB, depending on performance gains after the card and PSU install, and it sounds like the CPU upgrade won't help much either, so I may forego that option, too. :sigh:

Thanks again for your advice. Any other tips that I should consider?


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## twajetmech (Jul 1, 2004)

I think you'll see greater benifit from the additional memory and dual channel memory operation than with the cpu upgrade. Xp loves 1Gb and really hums with 2Gb, more than that and its a point of dimishing returns on money invested. Most people report sluggishnes when not running in dual channel and typically there is a 5%-10% gain along with the smoother operation. Watch your temps and voltages when you do the upgrade, typical 400W psu's (you didn't state brand and model) only have 17-18 amps on the 12V rail, which is boarderline to bare minimum for a gpu that will be pulling 90-125 watts at full load (in comparison your cpu is pulling 85-135 watts at full load) that doesn't leave much for the rest of the system as the mobo takes about 100 watts, 30 watts for each hdd etc. If your temps do rise, consider upgrading the case fans to ones with higher CFM output, the 8600gt can get hot (80C !) under load.


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## Roadster (Nov 21, 2007)

The new PSU is a Bestec ATX-400W, the exact same make and dimensions as the existing Bestec 300W PSU in the unit currently, and also the same make & model used by HP in their Pavilion media computers (slightly higher end than my Pavilion model). The specs for the video card called for a minimum of 350W, so I thought there would be sufficient overhead available with a 400W PSU.

Can you check the specs for the ATX-400W and let me know if it will be sufficient, in light of you concerns? I'm traveling home today from a business trip and pecking out this reply on my Motorola Q smartphone as my plane is about to board, so I can't readily do a normal Google search.


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## Roadster (Nov 21, 2007)

OK, I found the relevant specs after I got home.

Here is the spec sheet for the Bestec ATX-400W power supply unit...

http://www.power-on.com/atx12vhp400bt.html

Note: Max current is 17 A on +12Va

Here are the specs for the EVGA GeForce 8600 GT graphic card...



> Specifications
> Download PDF Spec Sheet
> 
> Performance
> ...


I only noticed the wattage spec before. I didn't see the amperage spec in parentheses.

Unfortunately, hardly any of the ATX power supplies on the following list meet the 22 Amp minimum spec...

http://www.atxpowersupplies.com/choosing-a-power-supply.htm

:sigh:


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## bpbp00 (Dec 14, 2007)

twajetmech is right on the 2x 1gb memory being better than 3 gb. I have run Sandra benchmarks on both the 2x 1gb and 3 gb and all are faster by about 6-8%. I also have a picture loading application that loads a rather large picture in 7 seconds using the dual channel and 8+ seconds with the 3 gb. So that is the way to go on the memory. As far as the mobo, the only thing I don't like about it is the fact that I can't overclock it, but it's still the fastest of my 5 desktops. Good luck with the upgrade.
Bob


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## bpbp00 (Dec 14, 2007)

Oh, 1 more thing on the dual channel, the 1gb memory sticks MUST be installed in the same color slots (usually 1 & 3 or 2 & 4) - one is black and one is blue. Both are hard to get at on my mobo which is the same as yours. I have to disconnect both of the mb power supply plugs and move them out of the way to install the memory. And don't do what I did. I installed the memory, closed up the PC, moved everything back where it belonged on my desk, pushed the power-on button - NOTHING !! I forgot to plug in the two power supply cables. 
Bob


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## twajetmech (Jul 1, 2004)

these psu's will have more than 24V on the 12V rail ! I don't care much for multi-rail psu's
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703011
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703005
http://www.newegg.com/Product/Product.aspx?Item=N82E16817703001


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