MSi Geforce 760 vs. Sapphire Radeon 7970

Today, NVIDIA releases their GeForce GTX 760. It uses the same GK104 graphics processor as the GTX 660 Ti, GTX 670, GTX 680, and GTX 770. MSI has overclocked their GTX 760 out of the box, but with only a relatively small overclock that provides a 3% performance improvement over the reference design. The new card delivers an impressive 22% performance improvement over the GTX 660 but is also priced $60 higher. In the product stack, the GTX 760 will replace the GTX 660 Ti, with the GTX 760 GAMING providing a performance that is 8% higher at $20 less. Compared to AMD's lineup, we see the card 11% faster than the Radeon HD 7950; the HD 7950 Boost variants should roughly match its performance but is more expensive.
While all other companies cheapen out by using more affordable coolers, MSI goes all-in, using the same TwinFrozr cooler as on the GTX 770 GAMING. This more powerful cooler provides fantastic cooling performance, resulting in low temperatures and low noise levels. Other cards are quiet in idle too, but MSI's card is by far the quietest during gaming. With just 27 dBA, it is quieter than most other cards on the market in idle while still packing a serious gaming punch. Any gamer who's looking for the lowest possible noise at 1080p full HD will certainly enjoy the GTX 760 GAMING.
While AMD's HD 7950 comes with 3 GB of VRAM, the GTX 760 "only" uses 2 GB, which is plenty considering both cards are just too slow to play any game at resolutions that require more than 2 GB of VRAM. Overclocking works well and provides an easily accessible performance boost of around 18%, making the card faster than the GTX 680 and HD 7970 GHz Edition. Pretty nice for a $260 card.
MSI's card also reduces power consumption slightly over the NVIDIA reference design, which helps with its Performance per watt score. Other GTX 760 cards we tested are at the end of the GK104 spectrum. MSI's card sits right in the middle, which certainly benefits temperatures and noise levels as there is less heat that needs to be cooled.
According to MSI, they expect their card to retail at $260, which is a very reasonable price premium of $10 over the reference design. When looking at cards for serious gaming, this is the card offering the most bang for the buck. The cheapest AMD HD 7950 retails at $10 more, is 11% slower, but comes with three games. So if you absolutely must keep cost down, the HD 7950 would be a cheaper option after selling off the game coupons. Source: http://www.techpowerup.com/reviews/MSI/GeForce_GTX_760_TF_Gaming/32.html

7970 gets my vote
http://gpuboss.com/gpus/Radeon-HD-7970-vs-GeForce-GTX-760 <-- this might help you a bit

Their both great choices i would go with the MSI GTX 760 because it's newer,quieter,consumes less power and runs cooler

if you max everything out and the video card doesn't have enough ram it has to go to the system ram which is a lot slower than graphics ram and you get hiccups while gaming, the more goodies activated, the more ram gets used, Some games use lots of ram, I heard some guy who plays skyrim with all his mods use actually 3.5gb of vram... nuts

Just wondering, do you have a specific need for 4gb of vram? What resolution is your monitor and what and games will you be playing? You don't need more than 2gb vram unless you are playing skyrim or max payne 3 on a 1600p monitor.

If you had to choose between the two cards I would go with the 7970 because it offers 3gb vram and I know you won't use that much. It also offers 3 free games. And its more powerful than the gtx 760. The power/heat efficiency of the gtx 760 isn't worth the loss in performance when compared to the 7970.