What is the stock max TDP for a stock Dell Inspiron 660?

Any video card that does not require auxiliary power should be fine.  The PCI Express slot provides 75 watts. This is why the new GTX 750 and GTX 750 Ti would be the top-of-line performance cards that you can get now. Prior to this card, the HD 7750 was the best you could get for the 300 watt system.  Even under heavy load, I don't see where you would use more than 200 watts with either of these cards.  The TDP on the GTX 750 is 60 watts and would miles ahead in performance over the GT 620.  HERE are two GTX 750s I would recommend. 

I currently use the HD 6570 on the 660s model that only has a 220 watt power supply and it works fine. It uses the exact same amount of power as the HD 7570.  Even it states a 400 watt power supply requirement. Manufacturers always overstate what is actually needed just to cover a system that might be fully loaded with hardware and I'm sure you don't have 5 hard drives running.  Based on what you will use it for, I don't see this card ever drawing more the 40 watts.   Most of the time, it will probably not need more than 25 watts.  The power draw only goes up a lot when doing heavy 3D gaming.  

So you're saying a 75 watts Radeon HD 7570 should be good to go for the system? No chance of it frying up my PC? I just need to be extra sure as I am not the sole user of the PC. My whole family uses it, and if there's any issues due to this, I will need to shoulder the blame.

I have just heard about the GTX 750 myself, but it is just priced a bit too high for now. I can get second hand HD7750 and GT640 for bout half the price. Also, I am mostly a 2D gamer so I think either of those will fit the bill.

Still, disregarding the GTX 750/Ti, I would like to seek official assurance from Dell that cards up to 75 watts TDP should work fine with the Inspiron 660's stock 300 watts PSU.

Also, can you please tell me why even the GTX 750 despite using just 55 watts TDP says you need a 400 watts PSU? The 75 watts HD7750 also says it needs 400 watts.

This is my first time upgrading my GPU, so please forgive me if I may seem to naive.

Ok. Look at this benchmark by PcGamer. Second to last result: http://www.pcgamer.com/review/nvidia-geforce-gtx-750-ti-review/ Says 164 watts under 100% GPU load.

That is platform power which means for the entire system.  

Just to confirm (sorry for bugging you), you are reasonably confident that my Inspiron 660 should be able to run the GTX 750 or 750Ti without much issues?

Yes.

And basically any card with a max power of 75W should in theory be able to run on it without killing the PC adversely in the medium to long run?

Yes.

And finally, since the GTX750 cards are ultra power efficient and emit low heat, do you think I need additional cooling and what not, or should the stock cooling suffice?

Stock cooling is fine.  

Also, do you think the noise emitted by the PC will dramatically increase?

No. 

Just to confirm (sorry for bugging you), you are reasonably confident that my Inspiron 660 should be able to run the GTX 750 or 750Ti without much issues?

And basically any card with a max power of 75W should in theory be able to run on it without killing the PC adversely in the medium to long run?

And finally, since the GTX750 cards are ultra power efficient and emit low heat, do you think I need additional cooling and what not, or should the stock cooling suffice? Also, do you think the noise emitted by the PC will dramatically increase?

Look at the TDP.  The card could not possibly draw 164 watts.  Nvidia does not allow it to draw more the 75 watts.  That may be for the entire system, but not the card itself.  

Factory overclocked versions may consume a bit more power, but it generally is not significant.  Some GTX 750 Ti models do offer the additional 6-pin connector on them so they can be more stable if you push the overclocks to the extreme yourself.  

Just to be sure, I may use it for heavy (i.e. 3D) gaming.

Anyways, I read more on the GTX750/Ti, and they do seem promising. Somewhat cheap as well.

When looking to see if they fit my PSU, do I need to look at the TDP or the load under 100% GPU power? For the 750Ti, it says TDP is 60 watts, but max load under 100% strain is 164 watts.

Also, I want to ask you about overclocking. Some cards are OCed out of the box. Does this contribute to a higher TDP than the stock/reference model, or not? For instance, the GT640 is confirmed by Dell officially to run on the Inspiron 660. It has been tested. But that model has clock speed of 900mHz and 65TDP. The OCed version by MSI meanwhile has a clock speed of 940mHz. Would the TDP be the same or different?

Ok. Look at this benchmark by PcGamer. Second to last result: http://www.pcgamer.com/review/nvidia-geforce-gtx-750-ti-review/

Says 164 watts under 100% GPU load.

Also, if you can help me understand whether OC affects TDP or not, I would very much appreciate it.

For instance, the two following GTX 750 cards. One is OC by 200mhz for both base and boost speeds. How will this affect the TDP? What kind of an effect can that sort of OC have on my PC? Is there any side effects to choose the OC version or not?

http://www.amazon.com/EVGA-GeForce-Dual-Link-Graphics-01G-P4-2751-KR/dp/B00IDG3NDY/ref=sr_1_1?s=electronics&ie=UTF8&qid=1393183095&sr=1-1&keywords=gtx+750+1gb+gddr5

http://www.amazon.com/EVGA-Superclocked-Dual-Link-Graphics-01G-P4-2753-KR/dp/B00IDG3LUO/ref=sr_1_4?s=electronics&ie=UTF8&qid=1393183095&sr=1-4&keywords=gtx+750+1gb+gddr5

Ok, so I understand you correctly, the 164 watts is the overall power at the very max. And this is still safely below 300 watts. Is that what you're saying?

Considering the benchmarking PCs probably have some other high end components in there, is it also possible mine will run at a lower max power?

The maximum allowed power draw by design for the Nvidia chip is 75 watts.  Board manufacturers like EVGA may add a 6 pin so overclocking is more stable when exceeding the 60 watt TDP which in turn needs better cooling.  Usually, a factory overclocked card does not go much beyond the TDP rating. Overclocked cards generally run a bit faster providing more FPS in games.  You should have no concerns about a factory overclocked card.  It's when you push the clock speeds yourself in an attempt to get the most out of the card is when stability problems can arise so you need to know what you are doing.  The 6 pin just adds a cushion in this case for the overclockers to reach a higher stable overclock.  

I would have no concerns about the EVGA superclocked version.  It has always been very popular especially if it's around the same price as the standard card.  The GTX 750's do not add 6-pins anyway.  They are only on some GTX 750 Ti cards.  

Just like the ad says....

I would always choose EVGA's superclocked version if you're more into gaming and want to get that extra performance out of the card but don't care to do the overclocking yourself.  You do not need additional cooling with the card. You get the bonus of the copper core so I would have no concerns.  EVGA has a $5 rebate on this card so they're both the same cost.  It's a no brainer for me, but I'm sure you will have another question.  

LOL. Was there a touch if sarcasm to your last sentence? Nevermind, I understand. We all ask many questions the first time we do something.

I really do appreciate your help. the GTX 750 OC does seem like the best choice now.

Regards,

himmatsj