Price vs Peformance: Asus GTX 660 DirectCU OC or TI version?

Looking at your other parts it would be right to get a 660ti at least. With those parts I would even suggest the gtx 670 of asus(non top). Got one myself with lower end parts than you. Specially if you want to use some degree of Anti-aliasing you want more cuda cores and bandwidth imo. So between those two I suggest the TI.

Specially if your monitor is 1080p.
With a 670 you will max out 90% of the games with AA at 60fps steady.

When I had one 660 non-ti, it could play almost any new game on the highest settings with 40-50 FPS. A few games such as Far Cry 3, Battlefield 3 and Max Payne 3 I could play in high detail settings in 1080p but these games also have an "Ultra" setting and the game didn't have good FPS in ultra. A 660 ti might not be able to hit ultra in these games either. When I got a 2nd 660 for very cheap (newegg $168; both are the Asus OC DCII Top) and put it in SLI mode, every game is playing in the highest possible detail settings with at least 55-60 FPS. I got both cards for just under $375 after a few rebates. A GTX 670 costs around $400. My benchmarks indicate that the 660 SLI setup is around 20% better than a GTX 680. If you are short on cash and the Asus 660 is on sale again, I'd say go for it and then in the future you could always get a 2nd.

A 660ti also has 192-bit DDR5 VRAM, but it uses the GK 104 found in the 670 and 680 as opposed to the fully enabled GK 106 in the 660. The 660 ti uses 2 PCIe power cables, the 660 only one. This means less power consumption and less heat. Both cards have 24 ROPs, while the 660 has 80 texture units and the 660 ti has 112. These last two numbers are a better indicator of a GPUs "horsepower" than their core count. This is a review comparing the two cards with two similar AMD cards, the 7850 and 7870:

http://www.eurogamer.net/articles/df-hardware-geforce-gtx-660-review

This site is usually biased toward AMD, but the FPS charts show that between the 660 and 660 ti on most newer games are fairly even in terms of FPS. The 660 ti beats it when the FPS starts to go over 120 in less graphic intensive games like Portal 2. In this comparison, the two cards are not benchmarked, instead they are compared based on what their hardware is theoretically capable of:

http://www.hwcompare.com/13296/geforce-gtx-660-vs-geforce-gtx-660-ti/

And a review comparing the two and other Nvidia cards with a table showing specs of each card:

http://www.hardocp.com/article/2012/09/13/asus_geforce_gtx_660_directcu_ii_video_card_review#.UYPF87Uqa4c

For $100 more, I don't think the 660 ti is worth it. On paper, it beats the 660 obviously, but in real world performance, I doubt you will see much of a difference between the two especially if you are using a single monitor in 1080p or 1920x1200. Besides, if you are planning on using multiple monitors and higher resolutions and need to keep the card under $300, a 7870 or 7950 would be a better option. One display, 1920x1200 or below and a 660 is the best bang for your buck.

Asus DCII OC GTX 660 for $189 plus a free copy of Metro Last Night:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814121660

or you could wait for the new 700 series. However the 780(which comes first) will costs 600 and probably more. They say it comes out by the end of this month or beginning of June. You will have to wait several month after that before the 770/760 come out.

I was in this situation myself and decided I didn't want to spend $600+ nor wait till autumn for the 770.
If you want to invest and last for some years to come, game at high settings,use AA etc. I would get a 670.

An other thing, the 660ti can be overclocked easily and it will perform close to stock 670.
However the 670 can be overclocked easily as well and perform like a 680. (which i did, got 1301pts in heaven maxed out 8xAA)

Check out the latest newegg (USA) deals: the same Asus GTX 660 OC card is on sale again for $168. This is the cheapest version of this card anywhere and probably one of the best versions of it as well.

http://www.newegg.com/Product/Product.aspx?Item=N82E16814121660&nm_mc=EMC-IGNEFL050313&cm_mmc=EMC-IGNEFL050313-_-EMC-050313-Latest-_-DesktopGraphicsVideoCards-_-14121660-L0B

If you get it from them, don't forget to enter the promo code. That code is worth an extra $20 off on top of the $20 mail in rebate from Asus. When this exact card was first released, it was selling for $250. Now, it is nearly $80 less. This is by far the best card in the $150-$200 range.

Here's the latest "Performance Per Dollar" chart from TechPowerUp:

http://www.techpowerup.com/reviews/Inno3D/iChill_GTX_650_Ti_Boost/28.html




And the latest Performance Chart:

http://www.techpowerup.com/reviews/Inno3D/iChill_GTX_650_Ti_Boost/26.html

That is when the 660 costs $210. For the next few days, it costs $168 and it is the overclocked version. If you take those facts into account, this week the Asus GTX 660 OC is the best bang for your buck hands down. On newegg right now, this card is cheaper than a GTX 650 ti 2 GB boost's retail price. Some are on discount such as the EVGA which is $149 after a $25 MIB. All the other 2 GB 650 ti boost cards are $170-$180. Hell, on the chart you posted, the card that review is about (Inno3D) is not as good a value as a stock GTX 660 for $210. Right now, the Inno3D card is £125 or around $195 (USD). Sure, next week the charts become true again, but what I said in my last post I meant for when it is on deep discount like it is today. The only reason I posted that is to let the OP know it was on sale again since he/she is interested in buying that exact model.