The GeForce GTX 1660 Ti started off as a rumor with many media outlets ignoring the leaks. While that's going on, you'll find that you've payed around $279 for the auto - which is pretty gosh-darned reasonable for a brand new GPU.
As for outputs, the reference version of the GeForce GTX 1660 Ti will come with one DisplayPort 1.4, one dual-link DVI, and one HDMI port (no confirmation so far on whether this is 2.0 or the newer 2.1 interface).
The GeForce GTX 1650 will be more of a budget solution for gamers, compared to the higher end models. Nvidia promises that overclocking is easy with a boost clock of 1.8 GHz, setting the standard of 120 frames per second in full 1080p games like Fortnite and Apex Legends.
In terms of specs, the GTX 1660 Ti comes with 1,536 CUDA cores, 6GB of GDDR6 memory running at 12Gbps and a boost clock of nearly 1.8 GHz (1770MHz). We should see cards from partners including Asus, EVGA, MSI, Zotac, PNY, Gainward, Palit, and Gigabyte.
Folks who've had a chance to benchmark a card (such as Anandtech) put it in the performance class of about 30 percent or so better than the GTX 1060. That's in alphabetical order there, not necessarily in order of quality or features. Just in case you were wondering, SLI isn't supported just like all the other mid-range GeForce cards and is reserved for x80 stack of GPUs, not that it actually works most of the time.
NVIDIA suggested today that this card's dedicated hardware encoder has the ability to bring 15% improved efficiency over "prior-generation graphics cards" and is made to roll right with Open Broadcaster Software of several sorts. NVIDIA claims the new GPU is 1.5x faster than the GeForce GTX 1060 6GB, and up to 3x faster than the GTX 960 from 2014.
We'll have to wait and see how performance shakes out.