Why put money into an old technology machine.  Even with upgrades it will still be an "old technology" PC.

There are later refurbished models (4 digit models) sold that would be a better investment.  

However, the Dell OptiPlex line is sold as a "business" PC and not a consumer or gaming.  

what 980 is it, MT, DT, SFF , must I guess that and what mobo is inside? 

9 years old today 2010 made.

the chips set there dictates what cpu you run.

this is no gaming PC , no game stated, so assume $60 AAA+ games, that, there are 100,000 games for 30 years.

the word game really means zero to me , lacking 1 example.

in most cases as poster said your  upgrade will not make you happy,  for AAA games.

the rules are simple:

• The chipset rules for you PC, can not be cheated. Intel Q57
• Socket VRM regulator power limits
• BIOS limits.

as a rule Dell does not check every CPU made after the PC was made, long ago. why would they. with 10,000 PC models, ? go broke doing that. no?

but you  can,  buy what you want and try it.

or learn to google what others did

learn to go to the top bench mark web sites (passmark?) see all 980 comments there. see?

the Q57 limit is clear, IDK dells BIOS code, nor all they do in BIOS and is not DOCUMENTED but do upgrade it.

here is the limits off the top limit page. 1st google hit btw.

http://www.cpu-upgrade.com/mb-Intel_(chipsets)/Q57_Express.html

gen 1 intel (old)

i7-880 - BV80605002505AG / BX80605I7880

95w TPD, if the MOBO (none stated no PC stated) can handle 95watts this might work.

 what works only you can do by self or google others,

this is no gaming PC, sorry, not in the modern sense. of word. AAA+

Dell, many times does a custom implementation of an Intel chipset. Thus what CPU, for example, that it will support may not fully support all the models Intel will list.  Have seen that over the years here.

https://www.dell.com/downloads/global/products/optix/en/optiplex-980-tech-guide.pdf

https://ark.intel.com/content/www/us/en/ark/products/42706/intel-q57-express-chipset.html

https://www.amazon.com/Intel-i7-870-Processor-Socket-LGA1156/dp/B002KQ5KEI/

Intel Core i7
i7-860 - BV80605001908AK / BX80605I7860 / BXC80605I7860

i7-870 - BV80605001905AI / BX80605I7870 / BXC80605I7870

i7-875K - BV80605001905AM / BX80605I7875K

i7-880 - BV80605002505AG / BX80605I7880

Hi, 

I got the 980 SFF on xmas last year, I used to be a gamer but have been out of the tech loop for a decade, so coming back I bought what sounded good and suitable without being a $killer.. I always buy on ebay, and used or refurbished, and have over 50 purchases and 0 loss in money,, if it was the wrong part, returns accepted, and if they malfunction (Manu. defect) free replacement.

But don't always listen to the "experts" listen to experience talking. I don't know what your gonna use your platform for, but I happen to have an OptiPlex 980 with the i7-880 (hyperthread tech. 4 core 8 threads, also the 880 is able to be overclocked to where most other LGA 1156 CPU's aren't. I got my for light-moderate gaming, document management as well as pictures and video editing. I'm guessing you had similiar ambitions. I've put $300 into my rig and bought a 44 inch Roku TV for $150 so $450 total, and for the same speed and performance it should go for around $700. There are 4 or 5 processors faster than the 880 but again, not able to be overclocked so are they really faster? they aren't worth the 80-300 price tag for sure. I would recommend just going up to the 880, and if it's still not doing what you want it to do then consider a newer mobo. But I'm happy with mine. and after some trial and error, I found that the GT 1030 suit's the system great. I can go faster but not much and again, price jumps dramatically. Basically a 2gig GDDR5 or a 4+ gig GDDR3 will get the job done beautifully. I also recently jumped up to the 1 gig SSD for like $75 that boosted the loading and processing even more. Look into that if you haven't already.  Good luck to ya and hope this helped even a little.. also, don't forget to update your bios! 

I'm glad I found this thread. I was considering the Optiplex 980 as well. But not as the "Optiplex 980". I am going to pull the board out and place it into my old XPS 720 case. A beautiful case that needs new life. Considering it will only be used as a media center attached to my TV.

Unless of course there is an even better BTX board with a slightly better chipset I could try?

@fastvan67 

Please Press the blue Accept as Solution button below if this post answers your question.

OptiPlex 980 Technical Guidebook Page 11
Processor

Quad Core processors require a discrete add-in graphics card as there is no INTEL HD graphics onboard. 

Optiplex 980 tech guide

https://ark.intel.com/content/www/us/en/ark/products/42706/intel-q57-express-chipset.html

https://www.amazon.com/Intel-i7-870-Processor-Socket-LGA1156/dp/B002KQ5KEI/

Intel Core i7
i7-860 - BV80605001908AK / BX80605I7860 / BXC80605I7860

i7-870 - BV80605001905AI / BX80605I7870 / BXC80605I7870

i7-875K - BV80605001905AM / BX80605I7875K

i7-880 - BV80605002505AG / BX80605I7880

Re: I was considering the Optiplex 980 as well. But not as the "Optiplex 980". I am going to pull the board out and place it into my old XPS 720 case

It is going to be difficult or almost impossible for this swap project.  720 uses Dell proprietary ribbon cable of front power switch circuit board to 720 multi pin header.  The 980 board uses completely different front panel multi pin header not interchangeable w 720.  Thus you would find it nearly impossible to turn on 980 board using 720 power switch, unless you move the entire 980 front panel with the board into 720 case and leave the FIO hang loose in case, not a great option.  720 also uses proprietary nonstandard psu.  It is incompatible w 980 mobo.  So a psu swap is also mandatory.  Lastly unless you figure out a way to rewire 720 front LED, the LED will not turn on any more.  The 720 LED are controlled by 720 mobo bios. After board switch they would not turn on unless you hardwire them.  Some one has done it but when asked how he did it no reply was received,