Upgrade advice: HD7870Ghz, HD7850 or HD7970?

I'm looking for some opinions and advice on the subject mentioned graphics cards. PC upgrades are new to me and I'm not sure which would be the best card for my system and was hoping to get some advice from you knowledgeable folks.

My rig is an i7 920 (2.66Ghz) with 12GB Ram and I'm currently using a HD5870. My rig is mostly used for gaming: XCom: Enemy Unknown, Skyrim and Far Cry 3. I presently run Skyrim and Far Cry 3 at 1920x1200 resolution on High settings but I've noticed that some games releasing this year will be rather taxing on the 5870. Plus it would be nice to run the above mentioned games at a higher quality.

I've narrowed things down to the HD7870Ghz, the HD7850 and the HD7970. I meet the system requirements on all cards, I'm unsure whether or not the cards will physically fit in my rig, but I've heard that the cards aren't that much bigger than the 5870. I've also heard that the newer cards don't get as hot as the 5870.

So experts, which card would best suit my needs? Or are they all relatively comparable?

essenbe said:

1st thing is what PSU do you have and will it handle the power requirements of the cards. Then it comes down to what you're willing to spend and what you want. I don't have any of them, but the number tells which is the best. The 7970 is the fastest of the bunch. Maybe this will help, Passmark ratings. But, be sure to check the PSU ratings for the wattage as well as amps. If you have multiple rails, how much on each rail?

MonkeyFunkR is already running a 5870. According to www.sapphiretech.com, the PSU requirements are similar. (Something seems inconsistent there, based on the PCI-E connections. A high-end 7970 could be good for something less than 375W.)

There are many review sites that measure the power consumption of cards under load or at least the total system power consumption under graphics load. Most measure the power at the wall circuit, so don't take into account PSU efficiency, which leaves you to make a guess of the efficiency to use to calculate how much power the PSU itself will draw. Other sites also measure power draw under a graphics intensive load like furmark stress test, then also at idle. They then subtract the idle and say that is the graphics card power. They have made a miscalculation however. The stress test program driving the graphics also uses more CPU power so what they are really reporting is the graphics power + this additional CPU power, which you again have to make a guess at. For instance, when I test graphics power consumption, I find furmark generates about 35W in CPU power (calculated by Realtemp).

I like the site linked below for video card reviews because they measure the power delivered by the PSU to the PCI-E bus so they are really measuring only the power the PSU delivers to the graphics card. The link is their results for the 7970 reference card (they have reviews for many of the non-reference 7970 cards out there too if you want to get specific):

AMD Radeon HD 7970 3 GB Review | techPowerUp

The bottom line is under furmark stress the card drew 270W maximum (furmark) and 189W peak (crysis 2).

essenbe said:

1st thing is what PSU do you have and will it handle the power requirements of the cards. Then it comes down to what you're willing to spend and what you want. I don't have any of them, but the number tells which is the best. The 7970 is the fastest of the bunch. Maybe this will help, Passmark ratings. But, be sure to check the PSU ratings for the wattage as well as amps. If you have multiple rails, how much on each rail?

This is embarrassing, but what do you mean by rails? As for my PSU I have a 800W unit.

essenbe said:

Their requirements are not clear to me. They recommend a 500W PSU for 1 card and 1 place says a 75W 6 pin connector is required for 1 card and later they say an 8 pin is required for a single card. I can only assume it requires both. Sapphire Vapor X 3GB.

The official AMD site does recommend that both be used. I haven't examined my rig close enough to know for sure how the 5870 is hooked up. I will check when I have a chance.

Bungee18 said:

Hi MonkeyFunkR,
Check this tool out, it allows you to compare any modern card out there. Here's the comparison between the 7850 and 7870.
AnandTech - Bench - GPU12
IMO the 7870 is not much better than the 7850 and not worth the extra money.
The 7970 is a different story. If your PSU and budget can handle it, go for it.
Here's a nice tool to calculate what your PSU can handle:
eXtreme Power Supply Calculator

I just got a second 7850 myself and I'm very happy with them.
Hope this helps.
Cheers,

J

I am leaning more towards the 7870.

Does it really matter which brand card I get? I had assumed it was simply an AMD branded card. I'm guessing they make the tech. My local Best Buy offers two different brands. Diamond and GIGABYTE. Newegg offers even more brands. Is there a huge difference nowadays?

Thanks Bungee and essenbe!! I'm checking out the reviews and pricing on the MSI Twin Frozr versions now. I've found a couple sales and I might be buying earlier than I planned. Thank you both for your help. It's much appreciated.