Upgrading processor on Optiplex 755 from Intel Core 2 to i7 (3rd Gen)

Sorry, I don't think your proposed CPU upgrade is going to work. :emotion-9:

Core i7 processors aren't listed in this table of Intel CPUs compatible with the Q35 chipset in your system, while your existing Q6600 is listed. You  can probably use this table to find the best/fastest available processor that will work with the Q35 chipset.

You can find instructions to replace the processor in this pdf.

Dell offered Vista 64-bit with this model, so I presume the Q6600 is a 64-bit processor, and in theory you should be able to run Win 7. That said, you'll need to find Win 7 drivers for the hardware installed in your system, eg video card, chipset, audio, ethernet etc. Some Vista 64-bit drives may or may not work with Win 7. You'll probably have to search these forums to see if anybody successfully upgraded to Win 7.

The 755 is not on Dell's list of systems supported for Win 8. That doesn't mean it won't run Win 8 but Dell won't help you and won't provide any drivers. Chances are, if there were Win 7 drivers for this system, they would probably work with Win 8 too. Again, search around these forums to see what others have done with the 755.

You should be able to replace the video card with something better, even without upgrading the OS. Just find one that fits the right slot and has a driver for whatever OS you'll be using.

Thanks so much for the quick response! I didn't expect to hear back so soon. So, I really appreciate it.

The pdf you sent indicated that the 755 supports 64-bit OS. But I hadn't considered that I might be limited to Vista. Currently, it's running on Win XP Pro (SP3) and would prefer to run Win 7 or 8 64 bit. So, big thanks for the heads-up on this and for the suggested route(s) to take... especially that link to the table of Intel CPUs.  

Forgive my lack of knowledge ... Am I understanding you correctly, that there are two different chipsets in my system - Q35 and Q6600 - or only one? Just wondering which chipset I should be looking for in that table. Or is there something I can look for in the CPU that indicates what the chipset is?

I didn't think of it originally, but the user guide mentions that switching to a 64-bit OS doubles the available RAM from 4-8GB. So, that could speed things up a little bit, even if I can't switch processors.

It was unclear in the user guide if I could add a second hard drive or not. If not, I suppose I could replace the existing,smaller 160gb hard drive with the larger 500gb solid state drive I bought. Can you think of any reasons why I might not be able to install an SSD on this box?

Thanks too for the video card tips. I'll be sure to check out the options available to me.

Thanks again!

- Jon

The Q6600 chip is the main processor (CPU) that does all the work. The Q35 chipset is an entirely separate chip (or set of chips) on the motherboard that tells the CPU when and how to communicate with all the other hardware. The CPU is plugged into a socket and can be replaced or upgraded. The chipset is mounted directly on the motherboard and should only be replaced by an expert, but it can't be upgraded. 

CPUs are designed to work with only one or a few specific chipsets and that pairing can't be changed. So you'd have to find a CPU that works with the Q35 chipset. The table at that link is a list of Intel CPUs that are compatible with the Q35 chipset. So you can only pick one of the CPUs from that list.

But before you select a potential upgrade CPU , you need to consider these things:

1. Does the upgrade CPU use the same motherboard socket as the Q6600? If not, you can't use it.
2. Does BIOS (another chip on the motherboard) support that upgrade CPU?

The first question is relatively easy. Google for the socket number used by whichever CPU you're considering and compare that with the socket number for the Q6600. If they're the same, OK. If not, choose a different CPU.

The second question is more difficult. The list of compatible CPUs shown in the manual for the 755, may or may not be up-to-date. When Dell releases BIOS updates, they sometimes add support for newer CPUs, but they don't tell us what new CPUs are supported. So if you find a CPU you like, we might be able to get Dell to tell you if it's supported by the latest version of BIOS. I don't work for Dell and can't promise they'll provide any info...

Switching to a 64-bit OS will allow you to go up to a max of 8 GB of RAM, using either 4x1-GB or 2x2-GB modules. That may speed things up over the 3-GB  you have now. Keep in mind that Vista isn't exactly speedy so that might negate a little, but probably not all, of the benefits of more RAM. Crucial.com is a good place to buy RAM for Dell PCs because they guarantee it works or they take it back.

You'll have to buy  a copy of Vista 64-bit (or Win 7, Win 8) because Dell won't provide it to you. You can buy a retail copy or -possibly- a Dell OEM version from eBay, etc, but caveat emptor! If it doesn't come with a valid product key number, don't buy it because Microsoft won't register it!  :emotion-5:

An SSD hard drive should work and Crucial sells some they claim compatible with the 755. A 500-GB SSD is ~$400 which is pretty pricey for an upgrade to an old system, on top of costs for added RAM, 64-bit OS, and possibly upgraded CPU and video card.

Maybe it is time to think about a new PC with the latest/fastest hardware and Win 7 or Win 8 pre-installed. Obviously, it's your money and you can spend it any way you want.

Have you tried cleaning out all the junk on the hard drive by getting rid of old tmp files, copying vids and pix onto CD or DVDs, etc? Have you defragged the hard drive recently? Have you stopped all the junk you don't need from running in the background? All that will help speed up the system too.

I found this posted by one of the Dell forum moderators as possible upgrade CPU options for the 755, quote:

Dual Core, E8400, 3.0G, 6MB, 1333FSB, 65W, E0

Quad Core Q9550, 2.83G, 12MB, YOR, C1

And you will need to update to the latest version of BIOS (A21) before installing an upgraded CPU.

Also consider running the "Windows 7 Upgrade Advisor" before trying to put Windows 7 on there. It could save you a lot of time and trouble.

Samsung SSD 840 EVO is a solid SSD Drive. The SSD drive upgrade gives any pc, desktop or laptop, the most bang for the buck.

Next I usually upgrade to a 64 bit operating system. Usually Windows 7. But, people have had problems with Windows 7 64 bit on the Dell Optiplex 755. Driver issues I believe it is. So I don't recommend this 64 bit OS upgrade for your current PC, unless you think you can get it to work for you. Here is a link to a fix for this for your PC:    https://communities.intel.com/thread/8176       it may work? Look at this link also:    http://social.technet.microsoft.com/Forums/windows/en-US/c61ed7ce-7399-4eca-ab78-1273735b9333/compatibility-of-64bit-windows-7-on-dell-optiplex-755     it will probably work.

Next consider upgrading the video card to a better card with more memory. The more memory the better. Try Tiger Direct or Micro Center for your parts.

Upgrade your memory to 6gb Ram or more, 4gb if that's all she'll hold. But even when manufacturers say they max out at 4gb, they'll usually accept more and work fine, if you can find the larger chips of the same family.

Increase your Virtual Memory to 10240 mb, or less if you get a smaller SSD Drive.  Still try to set it to at least 6144mb. This will keep your system from locking up when you overload it.

After you've done all this, then consider upgrading the processor.  Try "optiplex 755 processor upgrade" as a search string in Google. This should get you started.... Good Luck!!!

-Bill60--

Why are you responding to a thread that's almost 2 years old?

I'm sure the OP decided whether to upgrade that old system or to buy a new one long ago. :emotion-5: