CPU Upgrade for a Dell Optiplex 755

[Andre Lopes]

Hi a friend's dad has an Optiplex 755 that he basically uses for common stuff, like web and emails only.

I would like to upgrade the CPU. However, Im not totally secure about the compatible CPU's for the motherboard So I would love if someone could shed some light and commentary.


Here is the current system information:

Processors Information
Socket 1 ID = 0
Number of cores 2 (max 2)
Number of threads 2 (max 2)
Name Intel Pentium E2160
Codename Conroe
Specification Intel(R) Pentium(R) Dual CPU E2160 @ 1.80GHz
Package (platform ID) Socket 775 LGA (0x0)
CPUID 6.F.D
Extended CPUID 6.F
Core Stepping M0
Technology 65 nm
Core Speed 1795.4 MHz
Multiplier x Bus Speed 9.0 x 199.5 MHz
Rated Bus speed 798.0 MHz
Stock frequency 1800 MHz
Instructions sets MMX, SSE, SSE2, SSE3, SSSE3, EM64T
L1 Data cache 2 x 32 KBytes, 8-way set associative, 64-byte line size
L1 Instruction cache 2 x 32 KBytes, 8-way set associative, 64-byte line size
L2 cache 1024 KBytes, 4-way set associative, 64-byte line size
Max CPUID level 0000000Ah
Max CPUID ext. level 80000008h
Cache descriptor Level 1, D, 32 KB, 1 thread(s)
Cache descriptor Level 1, I, 32 KB, 1 thread(s)
Cache descriptor Level 2, U, 1 MB, 2 thread(s)
FID/VID Control yes
FID range 6.0x - 9.0x
Max VID 1.325 V

Chipset
Northbridge Intel Q35 rev. A2
Southbridge Intel 82801IO (ICH9DO) rev. 02
Memory Type DDR2
Memory Size 2 GBytes
Channels Dual, (Symmetric)
Memory Frequency 332.5 MHz (3:5)
CAS# latency (CL) 5.0
RAS# to CAS# delay (tRCD) 5
RAS# Precharge (tRP) 5
Cycle Time (tRAS) 15
Row Refresh Cycle Time (tRFC) 36
Command Rate (CR) 2T
Host Bridge 0x29B0

Memory SPD
DIMM # 1
SMBus address 0x50
Memory type DDR2
Module format Regular UDIMM
Manufacturer (ID) OCZ (7F7F7F7FB0000000000000)
Size 1024 MBytes
Max bandwidth PC2-5300 (333 MHz)
Part number OCZ2N1066SR1G
Serial number FFFFFFFF
Manufacturing date Week 165/Year 165
Number of banks 4
Data width 64 bits
Correction None
Nominal Voltage 1.80 Volts
EPP yes (1 profiles)
XMP no
AMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 3.0-4-4-13-15 @ 270 MHz
JEDEC #2 4.0-4-4-13-15 @ 270 MHz
JEDEC #3 5.0-5-5-15-19 @ 333 MHz
EPP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
EPP profile #1 (full) 5.0-5-5-15-22-2T @ 533 MHz (2.100 Volts)

DIMM # 2
SMBus address 0x52
Memory type DDR2
Module format Regular UDIMM
Manufacturer (ID) OCZ (7F7F7F7FB0000000000000)
Size 1024 MBytes
Max bandwidth PC2-5300 (333 MHz)
Part number OCZ2N1066SR1G
Serial number FFFFFFFF
Manufacturing date Week 165/Year 165
Number of banks 4
Data width 64 bits
Correction None
Nominal Voltage 1.80 Volts
EPP yes (1 profiles)
XMP no
AMP no
JEDEC timings table CL-tRCD-tRP-tRAS-tRC @ frequency
JEDEC #1 3.0-4-4-13-15 @ 270 MHz
JEDEC #2 4.0-4-4-13-15 @ 270 MHz
JEDEC #3 5.0-5-5-15-19 @ 333 MHz
EPP timings table CL-tRCD-tRP-tRAS-tRC-CR @ frequency (voltage)
EPP profile #1 (full) 5.0-5-5-15-22-2T @ 533 MHz (2.100 Volts)

Monitoring
Mainboard Model 0HX555 (0x0000016F - 0x0055C0A0)

DMI
DMI BIOS
vendor Dell Inc.
version A08
date 02/19/2008
ROM size 4096 KB

DMI System Information
manufacturer Dell Inc.
product OptiPlex 755
version unknown
serial 8TQGJ3J
UUID {4C4C4544-0054-5110-8047-B8C04F4A334A}
SKU unknown
family unknown

DMI Baseboard
vendor Dell Inc.
model 0HX555
revision unknown
serial ..CN698617CL07F0.

DMI System Enclosure
manufacturer Dell Inc.
chassis type Lunch Box
chassis serial 8TQGJ3J

------------------

Basically, I Think a quad-core should be enough for a windows 7 rig.
However, Im not sure If I should pick a cpu with 65W TDP or 95W TDP.

According to the references below, from the dell forums, the Intel Core 2 Quad Q9450S should work fine.
What do you guys think? I wanna try to upgrade the current CPU to this Q9450S.

I know I will have to update the BIOS, thats not an issue at all.

Thanks in advance, any help is appreciated.


PS: No, he doesnt want a new cheap computer. A new CPU will do just fine for his needs.


References:

https://www.dell.com/community/Desktops-General/CPU-Upgrade-for-Optiplex-755-Core-2-Quad/td-p/3655365

 

[Lutfij]

You state that it's a Dell OptiPlex 775 yet the link you've provided and the S/N on your post state that it's a 755. On that note, which version/form factor do you own? You should compare the processors stated in the service manual, here, page-10 which is a Q6700. Your choices are limited due to the Q35 chipset.

 

[william p]

Look around in here.
http://www.userbenchmark.com/System/Dell-OptiPlex-755/3939
Q6700 is old info. newer BIOS supports newer CPUs. 95W limit and no Xeon swaps means Q9650 or q9550 are the best.
You can look at CPU scores to see how much difference there is. For 56W I like Q9505S.
With 95W CPUs you will probably need a heatpipe style cooler.
JP911 for SFF. 65W the aluminum brick will be OK.
I would get at least 4GB RAM DDR2 800, 6-8GB if you add a 2GB GPU (DDR5) 6GB with 32 bit OS, 8GB with 64bit.
You didn't mention GPU. GT 730 1GB DDR5 64 bit low profile would be nice for that.

 

[Andre Lopes]

Look around in here.
http://www.userbenchmark.com/System/Dell-OptiPlex-755/3939
Q6700 is old info. newer BIOS supports newer CPUs. 95W limit and no Xeon swaps means Q9650 or q9550 are the best.
You can look at CPU scores to see how much difference there is. For 56W I like Q9505S.

With 95W CPUs you will probably need a heatpipe style cooler.
JP911 for SFF. 65W the aluminum brick will be OK.
I would get at least 4GB RAM DDR2 800, 6-8GB if you add a 2GB GPU (DDR5) 6GB with 32 bit OS, 8GB with 64bit.
You didn't mention GPU. GT 730 1GB DDR5 64 bit low profile would be nice for that.

Hi!
Thanks for the answer.

So basically a Q9505S should work fine?

It has DDR2 and it seems it only has 2 slots. I couldnt find 4gb DDR2. Do you know where I could find it in London?

GT 730 1GB DDR5 64 bit would require a new PSU or case adjustments?

Thanks a lot for the answer!

 

[Andre Lopes]

You state that it's a Dell OptiPlex 775 yet the link you've provided and the S/N on your post state that it's a 755. On that note, which version/form factor do you own? You should compare the processors stated in the service manual, here, page-10 which is a Q6700. Your choices are limited due to the Q35 chipset.

Thanks for the heads up. Although, William mentioned the Q9505S.
It has a lower TDP. Im a little insecure if its really compatible.

 

[william p]

The Optiplex 755 if you have the latest BIOS from Dell supports E0 stepping CPUs. That's Q9650 and Q9550s ,Q9550
The Q9505s is an R0 stepping. I'm running one in my Optiplex 380 . I don't see any notes of Opti 755 having issues with R0.
It's on the list here. The CPUID# and wattage are in spec.
https://www.dell.com/community/Desktops-General/CPU-Upgrade-for-Optiplex-755-Core-2-Quad/td-p/3655365
I didn't look at the SFF MB. 4GB DDR2 exist but they're very rare and expensive in the non ECC, low density versions that Dell requires. With 4GB limit i would run a 1GB GT730 64 bit DDR5 card and run it at 720P resolution. There are 1GB low profile GTX750s,but it's up to you if you want to test the 25W GPU limit that much. It has been done. Q9550S is 65W also but kind of pricey.
JP911 is the heatpipe cooler for the SFF. I t can run the 95W CPUs.