Backwards compatibility to older CPU socket 775

chartbear

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Feb 28, 2013
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I've tried to upgrade my CPU on an HP machine with an IPIEL-LA3 mobo from an E5300 to an E8400 but it wouldn't post. The mobo specs say the board is compatible with Wolfdale and Yorkfield series CPUs of which the E8400 is one. May be a bad part or maybe some other incompatibility.

The seller suggests I try a Q6600 instead, which is not, in this case a Yorkfield but one of its predecessors. It is somewhat older and was produced with the 65nm lithography (?) instead of the 45nm of my current CPU. The likely performance of the two CPUs is roughly similar per comparison web site.

Is an older CPU likely to work on a mobo designed for the newer ones?
 

clutchc

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It may ahve been due to the fact that the MB BIOS needed to be updated in order for it to recognize the newer E8400 processor. If the Q6600's faster FSB isn't a problem, it should be recognized because it was a year older. But to be absolutely sure a different processor will work, you'd have to either have a CPU support list for the MB or access to the latest BIOS version for updating.
 

chartbear

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Feb 28, 2013
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I appreciate the input. I've done quite a bit of online research but I can only find this regarding the motherboard:

http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01746799&cc=us&dlc=en&lang=en&lc=en&product=4004523

It just says that Yorkfield and Wolfdale series are compatible in general. My assumption was that meant all of them.

HP scanner says my BIOS is up to date.

The FSB is interesting because the Specs say the board supports FSB of 800/1600/1333 but only supports RAM speeds of 800/1600. Thing is I am running 6 month old RAM (Crucial recommended) that is rated at 1333MHz currently. Could that be why the E8400 wouldn't run? I just assumed that my RAM just wasn't going to be used efficiently but could it be the problem?
 

clutchc

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The Q6600 isn't from the Yorkfield (4 cores) or Wolfdale (2 cores) processor family. It is from the Kentsfield (4 cores) family. So I would be wary of it until I knew someone with that MB was able to get it to be recognized. I still feel the reason the E8400 (Wolfdale) didn't work was due to the MB BIOS being too old. And HP or Asus (Pegatron) probably quit supporting BIOS updates after 2009 on that board. However...

If this is the BIOS version you have in your MB, I would think it would work with E8400 because the E8400 was introduced 1-7-2008 and the BIOS below was introduced in 2009.
http://h10025.www1.hp.com/ewfrf/wc/softwareDownloadIndex?cc=us&lc=en&softwareitem=pv-73791-1

What was the symptoms you experienced when you tried to boot with the E8400?
 

chartbear

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Feb 28, 2013
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Yes, that is the version of my BIOS 5.05 per CPU-Z. The symptom was a beep code as soon as I pressed the button, one short and one long over and over. Nothing on the screen, but fans were turning. I checked connections, pulled each RAM one by one, cleared CMOS, and reseated the CPU. Same thing. Put my old E5300 and it booted right up. So, either I got a bad part or some incompatibility that the motherboard maker didn't know or didn't communicate. Not sure who Pegatron is. I don't think they are really the manufacturers. I think I'm leaning towards bad part.
 

clutchc

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Pegatron is part of Asus, that's why I referenced Asus above. They have made all the OEM boards for HP and Compaq for years. That beep code sounds like it is memory related. Do you have the PC's owner manual? If so, check to see if it lists beep codes. Dell used to do that, but I don't know if HP did.

You MB/BIOS supports Wolfdale CPUs. Your MB's chipset (G43) supports 1333MHZ FSB. I can't think of any reason the E8400 wouldn't work.
 

clutchc

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I was going to suggest you try the E8400 processor with just one stick of memory in the 1st slot to see if it would boot. Preferably the stick know to work with the system.

Upgrading proprietary PCs is always a bit dicey. Especially older machines. It would not surprise me to find it is a memory error. The beep code leads one in that direction.