Dell Optiplex 755 CPU Problem

Question

Hello, I was told in one of the forums that a Intel CORE 2 QUAD PROCESSOR Q9650 SLB8W 3.0GHz 12M CACHE 1333 MHz FSB would work in my Desktop. I purchased it on E-bay and installed it with the already upgraded bios A22. It did not work. I tried to install my original that did work and now I cannot get it to even post. I have removed the battery for an hour and that did not help. I tried a different video card in case that was the problem. I get absolutely nothing on the monitor. I am at a loss. Does anybody know a trick or two to get it back up and running. Thank you very much for your time. Robb

osprey4 · Accepted Answer

What POST error or diagnostic lights do you get which indicate an error?

Here's your manual: ftp://ftp.dell.com/Manuals/all-products/esuprt_desktop/esuprt_optiplex_desktop/optiplex-755_user%27s%20guide_en-us.pdf

You might try clearing the CMOS.

osprey4 · Answer

Hi Robb, I do not see that CPU listed by Dell as compatible. What form factor do you have?

robbietpa · Answer

It's a desktop model. The large one. Also I now know the cpu won't work. I am just asking how to get my old cpu working again (2.4) Because I will then find one that will work after I get it up and running again. Thanks Robb

robbietpa · Answer

Hello When the computer starts I get nothing on the monitor at all ! No post no nothing. Also I get no error messages or no irregular lights flashing that isn't normal from when working normal. It sounds like it's booting but no video. I have already installed two other video cards to see if that was the problem and no go. I put everything back to oem. No unusual lights no boot post. Sounds like the hard drive is working everytime I reboot. I'm at a loss. I have removed the battery for an hour and that did not help, I have not tried setting cmos yet by jumper. Thanks for the replies. Robb

robbietpa · Answer

Hello I kept messing with the cmos jumper turning it on and off a few times and it finally booted. Thank you for all your replies. Robb

osprey4 · Answer

Glad that worked!

pompste · Answer

Let us know what CPU you will get that works with your Dell 755. I`ve got a dual core 3.00 ghz in my 755 and that works great! Superfast!

robbietpa · Answer

Thanks for the reply, I have purchased a Intel Core 2 Duo E8500 3.16GHz/6M/1333 Dual-Core Processor SLB9K. I was told this will work and I sure hope so after already buying two others that will not work for the sum of $150.00 already spent and another $30.00 spent for this one which is more than fair. But as you know these are really a work horse computer with an outstanding lifespan. I hope it's worth all the effort as I am going to use it daily around the clock 365 days a year to run my security system GV-1120. The best to all of you. Thanks for everything. Robb

MacGruber · Answer

Based on this I would've done the very same thing, [taking a chance that lack of a newer Dell BIOS update may cause CPU to not be recognized]

Intel® Processors and Boards Compatibility Tool:

Found 85 Compatible Processor(s) for Board "DQ35MP

Intel® Xeon® Processor 3000 Sequence

X3360 2.83 GHz 12 MB 1333 MHz

Intel® Core™2 Quad Desktop Processor

Q9650 3.00 GHz No 12 MB 1333 MH

spec - SLB8W

Intel® Core™2 Quad Processor

Q9550S 2.83 GHz 12 MB 1333 MHz
Q9550 2.83 GHz 12 MB 1333 MHz

Intel® Core™2 Extreme Desktop Processor

X6800 2.93GHz 4 MB 1066 MHz

processormatch.intel.com/.../CompatibleProcessors

Locked Topics – Desktops General

Dell Optiplex 755 CPU Problem

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