UNSOLVED
Dell Optiplex 780 USFF CPU
Hi all,
I have a Dell Optiplex 780 USFF pc with an Intel Pentium E6700 3.20GHz CPU, I was wondering what other CPU’s this PC supports?
I am looking to replace the CPU and RAM as the PC seems to lock-up even after it’s completed it’s POST. So for example when I press F2, it will hang on the Intel Matrix Storage Manager screen and not go into BIOS and the keyboard buttons do not respond when pushed.
I have performed a system diagnostic test and all basic tests come back as fine.
Many thanks!
893
0
Posted August 30th, 2022 13:00
It would not help upgrading the cpu on this 13 yr old small Vista computer even if you could. Save your money to replace it. The service manual doesn't even mention replacing the cpu.
Dell OptiPlex 780 Service Manual--Ultra Small Form Factor Computer
What you could replace is the coin cell battery for about $1 at any store that sells batteries. See the manual. A bad coin cell prevents booting.
883
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Posted August 30th, 2022 17:00
First (just in case), no waiting for the Dell logo or a keyboard light to enter BIOS. Repeatedly push F2 at startup.
In the tech guide, CPU upgrade options are on pg. 8. Top listed CPU for the 780 USFF is the Intel® Core™ 2 Duo E8600/3.33GHz.
For RAM options, search the guide using "memory."
879
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Posted August 30th, 2022 20:00
Many thanks for that. In that guide, it shows the RAM being upgradeable to 8GB on the USFF 780, have I understood that to be correct? I thought it was only upgradeable to 4GB max?
878
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Posted August 30th, 2022 20:00
Indeed, 8GB RAM is the max. May be you got the "4GB" idea from a different Optiplex? Just as an example, the 755 had 8GB max for MT, DT, & SFF; 4GB for USFF. 8GB is much more ideal for Win10 than 4GB.
871
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Posted August 30th, 2022 22:00
correct that USFF can support 2x4 gb = 8 gb ddr3 desktop memory.
859
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Posted August 31st, 2022 10:00
Most modern games want 8 gigs minimum and quad core cpu.
So update bios
Then add ram
Then install win10 oem dvd.
Update cpu to quad core
https://www.youtube.com/watch?v=J8ja79SlA-g
CT2K51264BD160B
Configuration ID: CT7339271
DDR3-1600 • CL=11 • NON-ECC • UDIMM • 240-pin • 1.35V • 2Rx8 • PC3-12800Doubles performance.
Dual vs Quad core
856
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Posted August 31st, 2022 11:00
Hi @speedstep,
According to the Tech Guide, the USFF does not support quads. Isn't that also a power and heat issue since the quads are 95w and the duos 65w? I thought that was the stance you used to take.
854
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Posted August 31st, 2022 11:00
You are correct
Intel® Core™2 Duo Processor E8600 , 3.33 GHz, 1333 MHz FSB is 65W. USFF power is too low to support 95W cpu.
DT is cheap however.
https://www.ebay.com/itm/155031965196
Tower is always recommended due to ability to support larger video cards.
So a DT shell without hard drive could migrate parts from the SFF without needing reinstall.
Tower is always a better investment.
https://www.ebay.com/itm/175362805070
If planning on upgrade further then should not be over $100 because 790 and 7010 and 7020 are a better deal.
0
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Posted January 2nd, 2026 09:10
Well, I do have an Optiplex 780 USFF too, and I am satisfied with my Core 2 Duo e8400. It used to be very high end in its time. It will be a solid choice, On the ram side I am having 6GB of DDR3 memory maybe a little bit less for today's standard but okay for web browsing, It can even run some AAA titles like- San Andreas at 1400x900, Modern Combat 5, GTA Vice City.... And I'm also having that BIOS related problem.....
GarethS10
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891
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Posted August 30th, 2022 13:00
I appreciate what your saying, however I got gifted the PC and would like to get it working properly if possible hence my question. I have already replaced the CMOS battery.