Dell Optiplex 745 CPU upgrade

You should update the bios to the last version using XP or DOS.Only 90nm or 65nm cpus will work and the smaller units cannot use 130W cpus.  FSB is limited to 1066 and the ram never runs over 800Mhz.

1333mhz fsb cpus are not working.

http://www.dell.com/downloads/global/products/optix/en/opti_745techspecs.pdf

PROCESSOR

Intel® Core™ 2 Duo 1066MHz FSB Socket T with Dual Core technology  XD, EM64T, 2MB and up to 4MB L2 cache, EIST and VT (E6000 series)

Intel® Pentium® D 800MHz FSB Socket T with Dual Core technology  XD, EM64T, 2x2MB L2 cache,  EIST, and VT on 950/960 (900 series)  

Intel® Pentium® D 800MHz FSB Socket T with Dual Core technology  XD, EM64T, 2x1MB L2 cache  (800 series)

Intel® Pentium® 4 800MHz FSB Socket T with HT, XD, EM64T, and 1MB L2 cache  (500 series)

Intel® Celeron® D 533 MHz FSB Socket  T with XD and EM64T (300 series)

Not in the Desktop SFF USFF. And only with latest bios and motherboard revision.  Further restricted to 65nm parts and 1066fsb.

So Q6700  INTEL SLACQ might work but also might require the COPPER Performance Heatsink.  Latest Bios HEIDEN_2.6.6.exe should be done BEFORE changing CPU.

http://downloads.dell.com/FOLDER00224415M/1/HEIDEN_2.6.6.exe

745 DT893 Conroe E6300, 1.86GHz, 2MB, 1066FSB, B2
745 DU362 Conroe E6300, 1.86GHz, 2MB, 1066FSB, L2

745c DU362 Conroe E6300, 1.86GHz, 2MB, 1066FSB, L2

745e  GT825 Conroe E6300, 1.86GHz, 2MB, 1066FSB, L1

The ram runs at 800mhz or less regardless of which cpu.

Sorry for so much questions. I have the Midi Tower. Is the Intel Core 2 Duo E4400 also compatible?

Hi,

I have a 745c that I'm about to upgrade to a Q6700.
The Dell KB is recommending BIOS 1.2.2 for the 745c. Is HEIDEN_2.6.6 better? Necessary for the quad-core?

Thanks,

Ran

Always update bios BEFORE changing CPU. For older systems like this you need an msdos boot diskette or XP with antivirus software uninstalled to be reinstalled AFTER bios update is done.

You cannot put quad core in Desktop or SFF or USFF due to power supply limitations.