The information you've linked indicates that TDP is the same for both 1060 and 1660. I also refer to online sources, of course. And I already said that I didn't quite know why the 1660 cards all seem to have 8-pin connectors, if they really are only 120W.

I also know what the PCIe spec says about the 6 vs 8 pin power connectors. And I'm telling you there's no way manufacturers would cut their own throats by using an 8-pin connector if they could use a 6-pin connector and thus sell more units.

There is obviously a reason all the 1660 cards (that I've seen so far) have 8-pin connectors. The 1660 reference design may be 120W TDP, but the OEMs are clearly exceeding the 150W allowed by spec for 6-pin connectors. As an educated guess - although I already said I wasn't sure why - I think it probably has to do with OEM designs running the 1660 faster than the base clock of 1530 MHz**

** a quick review of the 1660 cards on sale at NewEgg right now : All the ones I looked at have 8-pin connectors, and all indicate clock speeds higher than the base 1530. Effectively, this is overclocking, and any overclocker can tell you it (almost) always involves more power. That explains the 8-pin connector: They're obviously exceeding the 150W a 6-pin connector can provide, and in fact some of them appear to be very aggressive about it, with boost clocks beyond 1800 Mhz; more than 18% faster than the base clock.

Like I said, I have two of the 3G 1060s, and both of them have 8-pin connectors. Why would this be, if they adhered to the reference TDP of 120W? Simple: Because they're "SSC" (factory overclock models) and they can obviously exceed the 150W a 6-pin connector could provide. To prove the point, many of the 1060 models actually do have 6-pin connectors, and that's as clear proof as you can get that according to the PCIe spec, they cannot exceed 150W.

So...why else would some 1060s have 8-pin and some have 6-pin connectors? And why would the 1660s have 8-pin connectors, thus lowering potential sales, if they're only 120W?

Like I said, there's a need to actually understand the relevant specifications, and principles of electronics involved.

I'd really hate for the OP to buy a card that can peak up over 150W, and have his machine locking up or crashing due to the PSU being over-taxed when the GPU gets really busy. As I mentioned, then he'd be stuck having to either replace his PSU (as he said he didn't want to), or return the card. I believe there's no need for all that...he can secure a very good upgrade, cheaper in all likelihood, by just going with a 6-pin 1060 model (either 3 or 6G, depending on preference and budget/cost).

One final time: An 8-pin card may well work...but is that something worth taking a chance over? Will it work but just cause the aging PSU to suffer accelerated failure/instability? I'd rather go with something that will be stable and won't cause problems, and you can't prove that with a 5-minute YouTube video.

BTW if it's true that the rumored 1650 will run at the 75W provided by the PCIe slot, and it outperforms a 1060, it may well be a better choice - when it's released.