8900 and 8700s are almost identical for graphics card upgrades.

lots to read here.

http://en.community.dell.com/support-forums/desktop/f/3515/t/19611037

my .02 for a GTX 980 ti - get a new case with better airflow, and room for a bottom mount PSU.

750W high quality 80 plus gold like the EVGA 750 G2.

Thanks I will look up the: 750W high quality 80 plus gold like the EVGA 750 G2, you recommend. I am old and retired and not that techy. I will actually pay someone to install the new Power supply .

Buy a new case is just excessive at this time. In future if there is one, like I said I am old, I will not purchase a Dell, But get something built or a model that I am sure will meet my needs (computer artist).

If you could be so kind. I noted the is an Nvida gtx 980ti and what appears to be other models Pny, egva and others, will they fit in my case and slots?

You are right and wrong. My device manger says it is an R7-370, but I went back and review my purchase order form Amazon and it say R9-370. Very strange. Either way it is a sucky card compared to the gtx 980ti

spammer/banned

f you could be so kind. I noted the is an Nvida gtx 980ti and what appears to be other models Pny, egva and others, will they fit in my case and slots?

Read through the thread I linked above and you'll see several that have done GTX 980 and I think a couple of 980ti's.

I like MSI brand and have had great success with them. In XPS 8700s I've had MSI GTX 760, 770 and 970's.  I can't cost justify more than a 970. 

EVGA is also a top brand and has reported excellent customer service.

ASUS is up there, and finally Gigabyte.

I'm not a fan of the other brands, but it is only from the review's I've read.

I tend to read techpowerup DOT com's reviews since they are fairly consistent.

A key consideration will be the height of the card, and the length of a tall card can be an issue.

good luck. 

I assume they all are using the Nvidia chip and all the difference is the manufacture board and fan. I looked and the is even one pricey liquid cooled  one out there

Yes, all GTX 980ti's will use the same chip. Keep in mind not all silicon is equal. When a company like EVGA or MSI or Gigabyte buys a bunch of GPU chips they test them and grade them based on how well they perform, and the higher performing chips tend to end up in products that are factory overclocked higher and may have better cooling to manage this etc.

For example: here is a review from a site that compares four different cards.

techreport DOT com/review/28685/geforce-gtx-980-ti-cards-compared

edit-> my posts with links are getting blocked for some reason. Replace the DOT above with a . and paste it into your browser address if you want to read the article.

Anyway, good luck with your search.

Oh, one more thing. I would not consider that hybrid card you referenced in an XPS 8x00 because there is no where to install the radiator.

Thank you for the info.