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July 29th, 2011 16:00

CPU Upgrade for Optiplex 755 - Core 2 Quad?

Hey guys!

       I've got a Dell Optiplex 755 desktop. It's a SFF, and I picked it up from the recycling room at my office. It just needed an HD fan, and it runs great. It's got a Core 2 vPro 3.0ghz in it right now, 4mb cache, and 1333-FSB.

It runs great, but I'd like to upgrade it to a slightly faster processor and I'm considering my options. I looked at the fastest Core 2 Duo I could get, and they only offer a 3.33ghz, however, it's something like $350 bucks for the processor.

I started thinking maybe I should see what else there is, and realized that there is also the Core 2 Quad, and the Core 2 Extreeme that both are available with 1333mhz FSB a larger cache, and still PGA775 (or whatever).

I'm curious, but do you guys know if it's possibly to install a Core 2 Quad, or a Core 2 Extreme in my Dell Optiplex 755? This PDF shows on Page 10 that it SHOULD take a Core 2 Quad. http://www.dell.com/downloads/global/products/optix/en/opti_755_techspecs.pdf

Is that the maximum that the BIOS will recognize / support? Can I use a QX6850?

 

Thanks guys!!!

Todd

Community Manager

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54.3K Posts

July 30th, 2011 16:00

These are the Quads we validated -
N652J 3.00GHz Yorkfield Quad Core Q9650, 12MB
F886J 2.83GHz Yorkfield Quad Core Q9550 12MB, 1333FSB, E0 
N650J 2.66GHz Yorkfield Quad Core Q9400, 6MB, 1333FSB, R0
MP627 2.66GHz Kentsfield Quad Core Q6700, 8MB, 1066FSB, G0

9 Legend

 • 

47K Posts

May 8th, 2012 09:00

The QX8200 May not work due to

CPUID   010677h

Core stepping   M1

I also think the 130W and 150W cpu's would require a Tower with Greater than

305W power supply AND the Copper heatpipe heatsink.

These are the Quads we validated -

N652J 3.00GHz YorkfieldQuad Core Q9650, 12MB Q9650

CPUID 01067Ah
Core stepping E0
Manufacturing technology (micron) 0.045
Number of cores 4
L2 cache size (MB) 
12
Features EM64T technology 
Enhanced SpeedStep technology 
Execute disable bit 
Extended Halt state
Extended Stop Grant state
Thermal Monitor 2
Trusted Execution technology
Virtualization technology
Core voltage (V) 
0.85 - 1.3625

F886J 2.83GHz Yorkfield Quad Core Q9550 12MB, 1333FSB, E0

N650J 2.66GHz Yorkfield Quad Core Q9400, 6MB, 1333FSB, R0

MP627 2.66GHz Kentsfield Quad Core Q6700, 8MB, 1066FSB, G0

Dell recommends applying this update during your next scheduled update cycle. The update contains feature enhancements or changes that will help keep your system software current and compatible with other system modules (firmware, BIOS, drivers and software).

UPDATING the bios must be done BEFORE trying another cpu.

Dell Dell Device
Release Date: 12/22/2011
Version: A21
Importance: Recommended
Download Type: BIOS
File Format: Non-Packaged
File Size: 2MB

O755-A21.exe

SLB5M

SLG9S

CPUIDs 10677 (SLB5M)
1067A (SLG9S)
Manufacturing process 0.045 micron

V core  0.85V - 1.3625V

CPUs, related to Intel Core 2 Quad Q8200  

Model Cores /
Threads
Freq. L2
cache
TDP Features
Intel Core 2 Quad family, Socket 775
   Intel Core 2 Quad Q9500 4 / 4 2.83 GHz 6 MB 95 Watt SSE4, VT, ESS
   Intel Core 2 Quad Q9505 4 / 4 2.83 GHz 6 MB 95 Watt SSE4, VT, TXT, ESS
   Intel Core 2 Quad Q9505S 4 / 4 2.83 GHz 6 MB 65 Watt SSE4, VT, TXT, ESS
   Intel Core 2 Quad Q9450S 4 / 4 2.66 GHz 12 MB 65 Watt SSE4, VT, ESS
   Intel Core 2 Quad Q9450 4 / 4 2.66 GHz 12 MB 95 Watt SSE4, VT, TXT, ESS
   Intel Core 2 Quad Q9550 4 / 4 2.83 GHz 12 MB 95 Watt SSE4, VT, TXT, ESS
   Intel Core 2 Quad Q9550S 4 / 4 2.83 GHz 12 MB 65 Watt SSE4, VT, TXT, ESS
   Intel Core 2 Quad Q9700 4 / 4 3.16 GHz 6 MB 95 Watt SSE4, VT, ESS
   Intel Core 2 Quad Q9705 4 / 4 3.16 GHz 6 MB 95 Watt SSE4, VT, TXT, ESS
   Intel Core 2 Quad Q9650 4 / 4 3 GHz 12 MB 95 Watt SSE4, VT, TXT, ESS

CPUs, related to Intel Core 2 Extreme QX9650  

Model Cores /
Threads
Freq. L2
cache
Multi-
processing
TDP Features
Intel Core 2 Extreme family, Socket 775
   Intel Core 2 Extreme X6800 2 / 2 2.93 GHz 4 MB 1 75 Watt SSE4, VT, ESS
   Intel Core 2 Extreme QX6700 4 / 4 2.66 GHz 8 MB 1 130 Watt SSE4, VT, ESS
   Intel Core 2 Extreme QX6800 4 / 4 2.93 GHz 8 MB 1 130 Watt SSE4, VT, ESS
   Intel Core 2 Extreme QX6850 4 / 4 3 GHz 8 MB 1 130 Watt SSE4, VT, ESS
   Intel Core 2 Extreme QX9770 4 / 4 3.2 GHz 12 MB 1 136 Watt SSE4, VT, ESS
Intel Core 2 Extreme family, Core micro-architecture, Other sockets
   Intel Core 2 Extreme QX9775 4 / 4 3.2 GHz 12 MB 2 150 Watt SSE4, VT, ESS

9 Legend

 • 

47K Posts

August 1st, 2011 07:00

Processor

Intel Core 2 Quad Q6700 Processor (2.66GHz, 8MB L2 cache, 1066MHz FSB, VT)
Intel Core 2 Quad Q6600 Processor (2.4GHz, 8MB L2 cache, 1066MHz FSB, VT)

Intel Core 2 Duo E6850 Processor (3.0GHz, 4MB L2 cache, 1333MHz FSB, vPro, VT)
Intel Core 2 Duo E6750 Processor (2.66GHz, 4MB L2 cache, 1333MHz FSB, vPro, VT)
Intel Core 2 Duo E6550 Processor (2.33GHz, 4MB L2 cache, 1333MHz FSB, vPro, VT)

Intel Core 2 Duo E4600 Processor (2.4GHz, 2MB L2 cache, 800MHz FSB)
Intel Core 2 Duo E4500 Processor (2.2GHz, 2MB L2 cache, 800MHz FSB)
Intel Core 2 Duo E4400 Processor (2.0GHz, 2MB L2 cache, 800MHz FSB)

Intel Core 2 Duo E2180 Processor (2.0GHz, 1MB L2 cache, 800MHz FSB)
Intel Core 2 Duo E2160 Processor (1.8GHz, 1MB L2 cache, 800MHz FSB)
Intel Core 2 Duo E2140 Processor (1.6GHz, 1MB L2 cache, 800MHz FSB)

Intel Celeron 440 Processor (2.0GHz, 512K L2 cache, 800MHz FSB)
Intel Celeron 430 Processor (2.0GHz, 512K L2 cache, 800MHz FSB)


6 Posts

May 7th, 2012 12:00

Would a Core2 Quad QX8200 work in the Desktop version of this motherboard?

Thanks

2 Posts

June 9th, 2012 16:00

Hello,

I have a Dell Optiplex  755 and  received a Intel Core 2 Extreme QX6700 BUT it will not work in my 755 it says it is

not compatible and will not boot. A Intel Core 2 Q6700 will work SO is the Intel Core 2 Extreme QX6700  a waste of $$

for me and will not work with a 755 at all OR.... what can I do???.

PLEASE HELP!!!

2 Posts

June 11th, 2012 02:00

Ok, so have you upgraded the PSU from the stock one? It is not powerful enough to run that CPU if you havent. I have an Optiplex 755 as well and I upgraded it to a 750Watt... So anyways did you upgrade it?

9 Legend

 • 

47K Posts

June 11th, 2012 06:00

BIOS must be Updated BEFORE trying a CPU.  Not all models are supported.

2 Posts

June 11th, 2012 08:00

Oh , yeah right I forgot, yea h you need the newest BIOS also... thanks @Speedstep...

4 Posts

December 22nd, 2012 17:00

Hi Chris I have a question for you. I am currently running a Q6600 on my optiplex775 I would like to know if it's worth the extra ££s to buy a Q9650... Would i see a great performance increase or notice much diffrence. Another Question is Iv'e just added more ram from 4gb to 8gb all the sticks are 800mhz but are diffrent brands and have diffrent latency's so the system has now set the ram clock speed to 667mhz would this be a performance issue for the current or if i was to buy. The Q9650.. The way I have worked it out it wont. As the bus speed of my current cpu is 266mhz and the ram is 333mhz as reported by cpu-z..And if im right the Q9650 has a bus speed of 333mhz so the Fsb:Spd ratio would be 1:1.. Is this correct??? Or would I benefit from faster ram bandwidth?

Many Thanks in advance Chris.

Rob

4 Posts

December 24th, 2012 16:00

Can anyone help with this..Please..^^^^^ Many Thanks in advance

893 Posts

December 27th, 2012 03:00

Just facts. Intel Core2 Quad Q6600 @ 2.40GHz - Average CPU Mark 2937, Intel Core2 Quad Q9650 @ 3.00GHz - Average CPU Mark 4376, which is 48% increase, you will notice the some difference in real world programming, is it cost effective, I don't know, would I do this upgrade, may be if it was the only option to increase the performance of my PC. You need to consider your reasons for an upgrade, what are you trying to achieve?

4 Posts

December 27th, 2012 08:00

Cheers Kisianik. I do a bit of gaming Plus Im a power freak, im just trying to achieve max power and performance, I just love upgrading to the max. Thank you for your answer, is it possible you could answer the other questions about memory bandwidth? Im worried about the BIOS downclocking the memory has impacted performance. And would this cpu work with a stock 280w psu. Thanks again for your help mate.. happy new year to you all..

893 Posts

December 27th, 2012 09:00

Q9650 actually requires less power and has higher maximum temperature! Regarding your RAM, I am trying to understand your question.

4 Posts

December 27th, 2012 14:00

Nice one, looks like i got a cpu to buy!!. Cheers. The question about the ram is that i had 4gb of ram running at 800mhz which was reported in the BIOS setup then i added another 4gb but because of the diffrence in spd's and latency's the bios has clocked the whole lot down to 667mhz..Please see previous post... What i want to know is am i going to loose any performance at all or will it all be fine no matter what processor i put in there because the FSB of the processor will never exeed the speed of the RAM... I dont want any bottlenecks... Many thanks..

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