7970 and 7950 crossfire

[Austinfitz1]

I have a 7950 and am looking at crossfiring. I've heard you can crossfire with a 7970, but can't find any benchmarks anywhere.

So i'm wondering does anyone here have any idea what kind of performance increase i would get crossfiring the 7950 with the 7970 compared to two 7950s. Is it worth the extra bit of money to go with the 7970 or should i just go with a second 7950?

 

Thanks everyone

 

PC Specs:

i5 3570k oc'd to 4.5 Ghz

msi Twinfrozer radeon 7950

8 gb hyperx blue

750 watt psu 

2 tb seaggate barracuda

250 gb samsung 840 evo (coming soon)

[hehehehhehehehe]

I don't think there will be any performance increase because when you X fire the two cards the fastest card will be clocked down to the exact specs of the other card.

[CwGoh]

You can, but the performance benefit is negagible over two 7950s since the 7970 has to scale back to 7950 speeds. I think.

[Canoas]

I don't think there will be any performance increase because when you X fire the two cards the fastest card will be clocked down to the exact specs of the other card.

Are you sure? From what i've read they don't down clock at all.

[Ghost Taco]

Are you sure? From what i've read they don't down clock at all.

Where'd you read it at? I've always thought that the higher end card clocks down to the lower end cards so basically you'd end up with two 7950s. http://www.amazon.com/Sapphire-Radeon-PCI-Express-Graphics-11196-19-20G/dp/B00CPLI74S/ref=sr_1_6?s=electronics&ie=UTF8&qid=1381550835&sr=1-6&keywords=radeon+7950 buying that would be your best option if you want to crossfire

[target39]

Both graphics card would have to perform at the same level, or else there would be serious crossfire synchronization issues. If you crossfire a 7970 with a 7950, the 7970 will not be optimized for use of its full capability because it has to allow the 7950 to "catch up" with every single frame.

Let's pretend you and Usain Bolt are running the 100m dash as partners and taking your average time (sum of Usain Bolt's and yours, divided by 2) as your final time. The rule is, you cannot be separated from each other by 5m or you will be disqualified. In real life, this means the frames cannot be produced at uneven intervals or else the game will look very stuttery and be rendered useless, if you're lucky enough for it not to crash. Because these are the rules, obviously Usain Bolt will slow down to your speed so that the distance between the two of you are within 5m. The same goes for the 7970. It will slow down to the capabilities of the 7950 so that they synchronize better to limit micro stuttering and other crossfire issues.

[hehehehhehehehe]

Both graphics card would have to perform at the same level, or else there would be serious crossfire synchronization issues. If you crossfire a 7970 with a 7950, the 7970 will not be optimized for use of its full capability because it has to allow the 7950 to "catch up" with every single frame.

Let's pretend you and Usain Bolt are running the 100m dash as partners and taking your average time (sum of Usain Bolt's and yours, divided by 2) as your final time. The rule is, you cannot be separated from each other by 5m or you will be disqualified. In real life, this means the frames cannot be produced at uneven intervals or else the game will look very stuttery and be rendered useless, if you're lucky enough for it not to crash. Because these are the rules, obviously Usain Bolt will slow down to your speed so that the distance between the two of you are within 5m. The same goes for the 7970. It will slow down to the capabilities of the 7950 so that they synchronize better to limit micro stuttering and other crossfire issues.

Love the analogy

[SkulD]

I have a 7950 and am looking at crossfiring. I've heard you can crossfire with a 7970, but can't find any benchmarks anywhere.

So i'm wondering does anyone here have any idea what kind of performance increase i would get crossfiring the 7950 with the 7970 compared to two 7950s. Is it worth the extra bit of money to go with the 7970 or should i just go with a second 7950?

 

Thanks everyone

 

PC Specs:

i5 3570k oc'd to 4.5 Ghz

msi Twinfrozer radeon 7950

8 gb hyperx blue

750 watt psu 

2 tb seaggate barracuda

250 gb samsung 840 evo (coming soon)

If i had a 120mhz monitor I could borrow the 7950 from my sis and pair it with my 7970 from my other rig and see if there is microstuttering. 

 

But what i really think would happen is that the 7970 will not work as hard as the 7950 so their loads will be different, maybe.

[Mukessh]

Your best bet would be just to get another 7950 . You won't gain anything by getting a 7970 , it will clock itself down . 

[Kuzma]

As stated by many others the 7970 would scale down - not only in clock speed because the 7970 outpeforms the 7950 at the same Hertz .

[Canoas]

Please stop saying nonsense, THE 7970 DOES NOT SCALE DOWN, it renders the frames quicker and then waits for the 7950 to finish. Anyone who has two different cards in crossfire and opened a monitoring program like msi afterburner will tell you that. However, some people with such setups also claim to have microstuttering, so I wouldn't risk it.

 

sources: overclocker.net and other forums like tom's hardware

[EricX2]

Please stop saying nonsense, THE 7970 DOES NOT SCALE DOWN, it renders the frames quicker and then waits for the 7950 to finish. Anyone who has two different cards in crossfire and opened a monitoring program like msi afterburner will tell you that. However, some people with such setups also claim to have microstuttering, so I wouldn't risk it.

 

sources: overclocker.net and other forums like tom's hardware

The first response in the post you linked to says 

 

 

 

If you put two different cards of the same series in crossfireX/SLi, the faster card will perform like the slower one. So basically it's more like 2x(the slower one).

[Canoas]

The first response in the post you linked to says 

Because it's the first post that is always right..

Scroll down and read the replies from Fantasy and Ken1649.