What happened to my 2.8E Prescott??

[Zizzo]

Greetings!

Ok here we go. I bought a 2.8E Socket 478 from AT around OCt. last year. I dropped it in my 848 mobo and ran it at 800FSB with some Corsair VS 512MB DDR. I also put the Zalman 7000AlCU without speed control (full speed). It ran great - although sometimes a little warm - 56-60C. I ran Climate Prediction on it.

One day about a month ago - I saw the video was blank but the monitor signal was on (green). I rebooted the box - and got fans but no POST. I replaced the RAM with another stick of Corsair VS 512MB DDR that I had in an identical mobo - same BIOS and everything. I put the CPU in the other mobo with the either stick of RAM - no go.

I put in a DDR333 and got POST. I ran all kinds of tests and put the DDR400 back in. No POST. I put the DDR333 (512MB) back in and then a stick of DDR266 (512MB) and it ran fine. Memtest told me it was still a 2.8 but with reduced L1 and L2 speed. The RAM obviously was either DDR333 or DDR266.

I decided to put the mobo back in the case and connected everything - no POST. The power supply would turn the fans but no POST. I changed out the supply and got everything working again. I'm doing Folding@home now for a few weeks.

I decided to put the DDR400 back in and no POST. The 2 sticks of DDR400 run fine in the other mobo and have many passes on Memtest. I put the DDR333 back in this 800FSB cpu/mobo and it works fine.

Even though I thought this CPU was a goner - it still runs at almost stock speed but not with the RAM it was designed to run with. So I ask your best and brightest minds - WHAT HAPPNED TO MY 2.8E PRESCOTT?

Thanks for reading.
Zizzo

 

[AkumaX]

Memtest told me it was still a 2.8 but with reduced L1 and L2 speed

?

 

[fbrdphreak]

Probly not your CPU, but your mobo from my guess. Try OCing your DDR333 to DDR400. Maybe that will help eliminate options
BTW, did you try that same CPU in a diff mobo w/same RAM? That will tell you if its your CPU if it works

 

[Zizzo]

Originally posted by: Zizzo
I put the CPU in the other mobo with the either stick of RAM - no go.

I have the CPU in the other mobo. I will try however to OC the RAM to DDR 400
Thanks

To AkumaX -

Originally posted by: Zizzo
Memtest told me it was still a 2.8 but with reduced L1 and L2 speed

I only had memtest to run on this mobo at the time. Let me get the numbers I had written down before and after the incident and I will edit. Thanks


Zizzo

 

[Duvie]

How does it boot with DDR 333 since the default is to run 1:1 with the 200fsb??? Did you change it??? If so, how since you cant post with 400ddr??? Jumpers on the board???

 

[AristoV300]

That is what I was wondering???

 

[Zizzo]

With all due respect to those in this forum - that is the same thing I am wondering.

I have an extensive background in computers and electronics. I started out in a Morrow MD-2 (CP/M) and moved to VIC 20 and such. I started OC with 286s by changing crystals on the mobo. I am A+, Network+ and MCSE (NT4) and working on my CCNA. I am not trying to brag but to show that I am really into computers.

So the reason why I am posting this phenomenon is that my 2.8E won't POST with the RAM speed it's supposed to POST with (DDR400) but rather a slower RAM speed (DDR333or266). There is no POST with either DDR400 on those mobos with the 2.8E. I have a 3.2C that works fine with 1 or both sticks of DDR400 on the same mobos (2 of them).

I have 4 848P mobos (jumperless) - 3 of them with the same BIOS and between 2 of them the CPU does what I explained above. I know it doesn't make sense - that's why I am asking you all have you ever seen such a strange thing?

I would love to hear your thoughts - thanks.
Zizzo

 

[Duvie]

Have you tried any other brand or type of DDR400???

It seems like a mobo issue, but you said this happens on 2 and it did work for awhile.....

I wonder if the bios by default is on s\auto and detects the eprom of the ddr sticks and revrts to DDR333 cause you put in PC2700 ram???

PC2700 and PC3200 have similar specs of vdimm that I recall though I have seen 2.5v pc2700 and 2.7v pc3200....are their vdimm adjustments on the board???

 

[AkumaX]

So the reason why I am posting this phenomenon is that my 2.8E won't POST with the RAM speed it's supposed to POST with (DDR400) but rather a slower RAM speed (DDR333or266). There is no POST with either DDR400 on those mobos with the 2.8E. I have a 3.2C that works fine with 1 or both sticks of DDR400 on the same mobos (2 of them).

Hmm... so youre saying the memory that you ran ddr400 w/ 3.2C doesn't work at ddr400 in a 2.8E in the same mobo.. interesting...

I still dont understand the reduced L1/L2 thing 😛

 

[Zizzo]

Originally posted by: Duvie
Have you tried any other brand or type of DDR400???

It seems like a mobo issue, but you said this happens on 2 and it did work for awhile.....

I wonder if the bios by default is on s\auto and detects the eprom of the ddr sticks and revrts to DDR333 cause you put in PC2700 ram???

PC2700 and PC3200 have similar specs of vdimm that I recall though I have seen 2.5v pc2700 and 2.7v pc3200....are their vdimm adjustments on the board???

I don't have any other DDR400 DIMMS besides the 2 Corsair VS 512MB. I went with DDR2. I will have to check my DIMM voltages - that is a good suggestion. I will try this and some other tips this weekend when I am home. Thanks for your input.

Zizzo