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Core 2 Due E6400 vs Pentium D 925

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June 4, 2008 12:49:46 PM

I've been searching, and reading, repeat process multiple times, and still can't find a good enough answer for me. So, here's the info and the question: I am currently running the latter CPU (Intel® Pentium® D Processor 925, sSpec SL9KA), and have in my possesion the former (Intel® Core™2 Duo Desktop Processor E6400, sSpec SL9S9). (In case anyone wants to know, I got the CPU for free when a client upgraded their system with a Q9300 CPU, and asked me if I "...could use the CPU, otherwise they were going to put it in a drawer somewhere." Of course I said I could "use" it! LOL)

The 925 is a 3.0GHz; the E6400 is 2.13GHz. The 925 has 4mb (2 x 2mb) L2 cache; the E6400 has 2mb cache (total.) Both appear to be comparable temp-wise. I'm ignoring the fact that the E6400 is up to 1066 FSB vs the 925's 800MHz FSB, since my mobo is only 800MHz FSB max, and only supports DDR2-667 (which is what I'm running.) I'm also not overclocking the CPU (either of them), so that's not a concern either.

I've been in computing for years, heck I've been around since the 8086 and earlier days, and we old-timers have a (bad?) habit of "higher clock speed + more L2 cache = better". But is that really true any longer?

The PC is mostly used for email, and as my main file server to feed videos over my local LAN to my modded Xbox running XBMC. Some gaming happens when my kids play on the computer. Not sure if any of that will factor in to the decision.

So, the real questions are: Should I swap out the 925 for the E6400? Will I really see any type of performance gain, given that the E6400 has a lower clock speed and less L2 cache? If the answer is yes, how much performance gain (roughly, of course) would I be looking at?
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June 4, 2008 1:02:37 PM

The E6400 destroys,demolishes,bombards,......... the Pentium D 925, definitely go for it

Intel Core2Duo has a whole different thechnology compared to Pentium
June 4, 2008 1:04:35 PM

First question is will your mobo support the 6400...bios wise...if so then yes put it in.....you should see anywhere from 10 to 20 percent increase...and less power consumption....
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June 4, 2008 1:05:15 PM

With what you do with your system, you will probably not notice much of a difference. The Core 2 architecture is vastly superior to the old Pentium D architecture. So much so that your E6300 will probably beat the P4D 925 in every application, energy usage, temperatures and defiantly overclocking. That being said, you will probably have to upgrade your motherboard to use it. With what you are doing, I doubt the costs could justify the performance increases.
June 4, 2008 1:12:38 PM

Of course I checked if my mobo could run the CPU; if it couldn't, I wouldn't have bothered asking. :p 

To answer the question directly, yes, my motherboard will support the E6400 (I'm running an Intel D945GCL. Speaking of which, aparently I was wrong earlier, since Intel says it DOES support up to 1066MHz FSB. D'oh!

outlw6669, there's no cost to upgrade.
June 4, 2008 1:15:02 PM

Smacks HotStuff2 over the head for dumb ass question... The E6400 could be the Pentium D 3.73ghz extreme edition a run for its money in all likely hood.

PS: No hard feelings but I find people learn quicker if it hurts :p 
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June 4, 2008 1:16:51 PM

If your board doesn't support it, just leave it the way it is.
There won't be enough difference between these 2, and since your board doesn't support the Core Duo, it will most likely end up degrading the performance as it will only be running at about 1.8ghz on an 800Mhz buss anyway.
I see that you found it will support it, then by all means definetly put in the Core Duo.

When you are talking about CPU's within the same family, yes more Mhz is faster as always has been. When you are talking about 2 different families, like the Pentium D you have vs the Core Dou, no, you cannot compare raw Ghz speeds any longer. The new architecture of the Core Dou allows it to do about 30% more work per clock cycle than the Pentium D can do. So realistically, if you have a 3.0Ghz pentium D, a 2.0Ghz core duo will perform about on par with it.
The core Duo will run cooler, and use less power, an probably show a little overall improvement. Whether you will notice it or not? Probably not.
June 4, 2008 1:18:09 PM

JDocs said:
Smacks HotStuff2 over the head for dumb ass question... The E6400 could be the Pentium D 3.73ghz extreme edition a run for its money in all likely hood.

PS: No hard feelings but I find people learn quicker if it hurts :p 
LOL c'mon, it wasn't THAT dumb of a question. :p  I'm just an old-school tech from the old days, like I said, and we old-timers have that mentality of "higher clock speed + higher L2 cache = better". Haven't bothered to really keep up with CPUs and what's a good upgrade to an existing processor. :pt1cable: 

Eh, what the heck. I'll pull the PC and drop it in, see what the benchmarks say. I got some time to kill this morning anyway. :kaola: 
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June 4, 2008 1:19:20 PM

HotStuff2 said:
Of course I checked if my mobo could run the CPU; if it couldn't, I wouldn't have bothered asking. :p 

To answer the question directly, yes, my motherboard will support the E6400 (I'm running an Intel D945GCL. Speaking of which, aparently I was wrong earlier, since Intel says it DOES support up to 1066MHz FSB. D'oh!

outlw6669, there's no cost to upgrade.



Ahh.
You got me when you said it only supported FSB800 :kaola: 

Hells yeah upgrade!
For a free upgrade, it will be cooler, more energy efficient and faster than your current P4D.
If you feel saucy, try to bump the FSB on your motherboard even higher.
The C2D series are legendary overclockers!
June 4, 2008 1:20:50 PM

jitpublisher said:
...When you are talking about CPU's within the same family, yes more Mhz is faster as always has been. When you are talking about 2 different families, like the Pentium D you have vs the Core Dou, no, you cannot compare raw Ghz speeds any longer. The new architecture of the Core Dou allows it to do about 30% more work per clock cycle than the Pentium D can do. So realistically, if you have a 3.0Ghz pentium D, a 2.0Ghz core duo will perform about on par with it.
The core Duo will run cooler, and use less power, an probably show a little overall improvement. Whether you will notice it or not? Probably not.
Excellent explanation. As long as I'm not LOSING performance, might as well drop it in, eh? :lol: 
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June 4, 2008 1:23:17 PM

Might as well......:) 
June 4, 2008 1:23:54 PM

outlw6669 said:
Ahh.
You got me when you said it only supported FSB800 :kaola: 
;)  i shoulda checked myself. Thought I did...guess I thought wrong. :whistle: 

outlw6669 said:
Hells yeah upgrade!
For a free upgrade, it will be cooler, more energy efficient and faster than your current P4D.
If you feel saucy, try to bump the FSB on your motherboard even higher.
The C2D series are legendary overclockers!
Unfortunately there's no options in the BIOS to do so, as this is an eMachine model T5226 I picked up for dirt cheap from Circuit City last year (open box display special, only cost me $149, couldn't pass up the deal, even for an eMachine.) :sol: 
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June 4, 2008 1:30:20 PM

Quote:
Unfortunately there's no options in the BIOS to do so, as this is an eMachine model T5226 I picked up for dirt cheap from Circuit City last year (open box display special, only cost me $149, couldn't pass up the deal, even for an eMachine.) :sol: 



Erm... An eMachine.
That kinda changes things.
Definatly worth trying but most prefab machines do not allow upgrading of the CPU. Sure the chipset will support it, but eMachine has to wright a BIOS to support the new C2D chips with it. Deifinatly check to see if they offer an updated BIOS before you start and best luck geting it to work!
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June 4, 2008 1:32:35 PM

Ahhh. Does the BIOS support the Core Duo?
If the BIOS doesn't, it won't set the speeds or voltage correctly......even if the motherboard officially does support the speed for it.
Prebuilt systems don't always have support written into the BIOS for upgrades like CPU's, just have to try it and see what happens.
June 4, 2008 1:42:40 PM

I don't see the chip working with a slower FSB than it was designed for.
June 4, 2008 1:47:20 PM

It's not a dumb question, ignore that poster

You seem to have basic needs for your intended computer use, you'll not really see much improvement in performance. As it's free though you might as well install it and it'll lower your power consumption too :)  As others have said check to see if there's an updated BIOS for your Motherboard and that it supports that CPU.
June 4, 2008 1:56:55 PM

Pentium D is much worse than Core2Duo.It isn't a dual core it's a dual chip!!It is better 2MB L2 Cache on dual core than 4MB on dual chip.E6400 is definitely much better.
June 4, 2008 2:16:38 PM

outlw6669 said:
Erm... An eMachine.
That kinda changes things.
Definatly worth trying but most prefab machines do not allow upgrading of the CPU. Sure the chipset will support it, but eMachine has to wright a BIOS to support the new C2D chips with it. Deifinatly check to see if they offer an updated BIOS before you start and best luck geting it to work!
Eh, not really. Trust me when I say I'm not an inexperienced user. ;) 

jitpublisher said:
Ahhh. Does the BIOS support the Core Duo?
Yes.

speedbird said:
You seem to have basic needs for your intended computer use, you'll not really see much improvement in performance. As it's free though you might as well install it and it'll lower your power consumption too :)  As others have said check to see if there's an updated BIOS for your Motherboard and that it supports that CPU.
It's already in and working. Had some Arctic Silver 3 still laying around (that'll tell ya how long it's been, eh? :lol:  ) so I put that on. Checked the BIOS just to make sure, and yep, it's all good.

San Pedro said:
I don't see the chip working with a slower FSB than it was designed for.
Maybe you need glasses or something. :sarcastic:  I'm only running DDR2-667 RAM, but that doesn't really matter that much IMHO. It's working just fine.

The Pentium D 925 had scored a solid 4.8 on the Vista Experince Index; the E6400 came in at 5.1. Slight increase there, for what it's worth (and being that it's just the Vista Experience Index, that's not much.) :p 

edit: Heh...just remembered I have some DDR2-800 sitting in my parts drawer, time to shut it down and put that in as well. :sol: 
June 4, 2008 2:37:57 PM

Darn eMachines/Intel BIOS doesn't appear to support more than DDR2-667 RAM. I put the DDR2-800 in, and the BIOS only shows it as DDR2-667. :heink:  There's a BIOS update from Intel for this board, but it won't let me install it; probably because it's for the retail version. I haven't found an updated BIOS from eMachines, not even on the unofficial support board. Not for this model, at least. :pfff: 

No worries though. DDR2-667 is good enough for now. :) 
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June 4, 2008 8:23:43 PM

DDR2 667 will work at 1:1 until 1333FSB.
June 4, 2008 8:44:57 PM

Hotstuff, hopefully, by now, you've already upgraded and you can see that the E6400 replacement was worth the exercise of the swap. Enjoy.
June 4, 2008 9:02:55 PM

The 6400 is about equivelent to a 4.36Ghz pentium D.
June 4, 2008 9:16:00 PM

HotStuff2 said:
Darn eMachines/Intel BIOS doesn't appear to support more than DDR2-667 RAM. I put the DDR2-800 in, and the BIOS only shows it as DDR2-667.

That is likely because of the RAM's SPD settings rather than any limit in the MB itself. If the BIOS allows you to manually set RAM voltage and timings, you should be able to get it running at DDR2-800. See this post for more info: http://www.tomshardware.com/forum/200599-30-memory-nooo...

OTOH, as shadow implied, you won't get any significant performance increase from running the RAM faster, since the CPU's 1066MHz FSB will be the bottleneck for any RAM speed faster than DDR2-533 (assuming the RAM is running in dual-channel mode).

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May 5, 2014 1:54:47 PM

an optiplex 755 will run ANY core 2 cpu out there. Including Quad Core's. For a lilttle more money you can get something that will rival the new G processors.
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May 5, 2014 2:50:03 PM

Mondoman said:
HotStuff2 said:
Darn eMachines/Intel BIOS doesn't appear to support more than DDR2-667 RAM. I put the DDR2-800 in, and the BIOS only shows it as DDR2-667.

That is likely because of the RAM's SPD settings rather than any limit in the MB itself. If the BIOS allows you to manually set RAM voltage and timings, you should be able to get it running at DDR2-800. See this post for more info: http://www.tomshardware.com/forum/200599-30-memory-nooo...

OTOH, as shadow implied, you won't get any significant performance increase from running the RAM faster, since the CPU's 1066MHz FSB will be the bottleneck for any RAM speed faster than DDR2-533 (assuming the RAM is running in dual-channel mode).



A OEM machine that lets you tweak ram timings? I haven't owned many pre built computers. But I have never seen a bios that allowed you to do that in a OEM machine?
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May 5, 2014 3:13:04 PM

If you put 800mhz ram in it will run at 800. But it is hardly worth buying new ram to go from 667 to 800. You wouldn't see that much performance difference.
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May 5, 2014 3:14:27 PM

As far as the CPU Clock being at 1066, the ram clock is independent from the CPU clock. Neither will affect each other.
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May 5, 2014 10:09:27 PM

The Core 2 Duo E6400 surpasses the Pentium D 925 by far by ease. Since your motherboard supports the Core 2 Duo, and will run at 1066MHz, then it's clear that the C2D will run circles around the PD.

With that said, if you're serious about upgrading and increasing performance, your motherboard may support Core 2 Quad's, which are still ranked under high-end in most benchmarks. C2Q's are likely to be supported if your motherboard can already take Core 2 Duo's. You may then install/upgrade your graphics card to something more modern; boosting your computer's performance. Finally, the component you'll notice make a difference in "performance" from use on a daily basis, and as well as a file server; you guessed it, a SSD. The latter will improve responsiveness, and you will be impressed with performance of your machine.

Not trying to sell anything, but if you're willing to put money in an upgrade; then the options are available. Generally the Core 2 Duo is by far better then your Pentium D anyhow. :) 

All the best. :) 
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May 5, 2014 10:33:31 PM



Or 6 year old threads in this case....

Seriously, let it die.
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May 5, 2014 10:34:05 PM

I am pretty sure a 945G chipset will not support Core 2 CPUS.
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May 5, 2014 10:34:57 PM

a b à CPUs
May 5, 2014 10:38:35 PM

YOUR MACHINE WILL NOT SUPPORT THE CORE 2 E6400.
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May 5, 2014 10:41:12 PM

How the fk did i get in a 6 yr old thread?
!