HELP! can i cross fire hd 6870 with hd7790

[tonyrowe]

I would like to cross fire my new card hd7790 with my old one hd6800 and know if i would get an improvement my machine is not the best but neither is my wallet, if i could get a pro answer on this and as to what i should do with my current setup would be much appreciated.

[profJim]

Re: HELP! can i cross fire hd 6870 with hd7790

AMD CrossFire FAQ - Requirements says:

within the same family model number. E.g. 2 x AMD Radeon HD6770

A good quality 650 - 750 watt power supply should be fine.
It looks like mixing 68xx and 77xx video card models will not work in CrossFireX.

[profJim]

Re: HELP! can i cross fire hd 6870 with hd7790

You're welcome.
A dual video card setup while gaming will result in higher temperatures and more fan noise, especially when the video cards are overclocked. A higher end single video card setup might be best if you sold your current video card. The bottom line is how fast are you willing to spend.
Your best value and performance might be with a single HD 78xx video card.

Checking video card reviews for each model will help you determine which setup is best for you. Keep in mind that each web site will use a different cpu/motherboard setup, so some of the performance results will differ with the same video cards. I prefer review sites like HardOCP where they focus on the overall gaming experience and which game presets could be used, rather than just reporting the maximum FPS results for each game.

A google search using: hd 6870 crossfire review provides links where you can see how much more performance a CrossFireX setup can provide. Depending on the game and screen resolution, the TechPowerUp review shows that FPS performance can improve by approximately 35% to almost 100%.

My GTX 460 SLI performance is close to a single GTX 470 or GTX 570 video card, but I'm using a six year motherboard and cpu.

Let us know which video card setup you end up with.

[tonyrowe]

Re: HELP! can i cross fire hd 6870 with hd7790

ok getting hold of another Gigabyte Radeon HD6870 1GB SuperOverclocked has proved to be harder than it looked all i could find was a Gigabyte Radeon HD6850 1GB
would them two crossfired give me more power than just going out and buying a Gigabyte Radeon HD7790 2GB Overclocked
now i understand that newer product would be better but if i can gain an overall increase in performance better than the single card seemed to make more sense to me
i have the required power to run it i think 750w

[profJim]

Re: HELP! can i cross fire hd 6870 with hd7790

It might depend on which games you are playing.
Unless someone has run both setups on their system, it will be hard to give a definite answer as to which setup offers better gaming performance. I prefer to compare reviews from the same web site, because their tests will usually include the same or similar benchmarks. When you compare reviews from different web sites, they often benchmark different games and use different systems with different processor models or brands (AMD versus Intel) and different motherboard models and memory. You also need to consider how much higher each video card setup can be overclocked, as this makes a difference.

In your case, I think that the best comparison is to find one or more top tier video card review sites that have reviewed a single 7790 video card and a 6850 CrossFireX setup using a system similar to yours. Ideally they would benchmark games that you prefer to play or plan to play in the future.

The TweakTown main site has an Ask The Experts feature where they answer questions like yours. You would need to include hardware details about your cpu, motherboard, memory and power supply. Go to Ask the Experts - helping with tech questions :: TweakTown and click on Ask us a tech question! Use this form. If your system is overclocked, include details about your overclocked cpu and memory speeds.

If the HD 7790 and 2 x HD 6850 systems have similar performance, you might want to buy the 7790 video card now and possibly buy a second 77xx card in the future for even better gaming performance.

[profJim]

Re: HELP! can i cross fire hd 6870 with hd7790

You're welcome, I think

I'm not familiar with Australian taxes or shipping charges, but I had a quick look at Video Cards - Radeon PCI-Ex 7xxx Series | Techbuy Australia for 7xxx video cards. I don't know which outfit down under has the best prices.

HD 7950 - 8 models from $339 - $400
HD 7790 and HD 7850 models vary in price from $188 - $255 each

My preference is to spend a bit more within a model family to buy a video card that has better cooling and lower fan noise.
When I bought my MSI N460GTX Hawk video cards their prices were in the higher end of the GTX 460 family, but they offered some of the best overclocking potential, excellent cooling and were quieter than most lower priced 460's. They also had a 3 year warranty where most similar cards only had a 2 year warranty. Most of the the time, you get what you pay for.

I'm not familiar with AMD cpu's and I don't know if your system might be cpu bound with a higher end setup with a single or dual video card setup. If your cpu isn't "strong enough", you probably won't get the best performance out of your video card setup.

From everything I've posted, it shows that there are many factors to consider to get the most out of your system. It would be a shame if you spent $400 on a video card setup if the gaming performance was held back by your cpu, even though you would be running with a single 1920 x 1080 monitor. To further complicate your decision, running your monitor at 1680 x 1050 resolution would let you use even higher game quality settings. It might help if you joined some gaming forums that are dedicated to the games you play most often. Hopefully you would get some good advice from gamers that have setups that are similar to what you have.

One contributor in my MSI Hawk overclocking thread had a setup similar to mine and his somewhat newer system was slightly better than my system. He later upgraded his system to a newer Sandy Bridge setup and was then able to upgrade with a higher end video card. At that point, his video benchmark scores left me in the dust.

Another thing to consider; if AMD is introducing newer 8xxx video cards in the near future, prices of the 7xxx cards will drop, possibly up to 10% or more. It's enough to drive us crazy.

[tonyrowe]

Re: HELP! can i cross fire hd 6870 with hd7790

ok I raided the pokets and found enough to buy

Gigabyte GeForce GTX 670 Overclocked 2GB

what is your thought and what should I over clock to?>

[profJim]

Re: HELP! can i cross fire hd 6870 with hd7790

Your new GTX 670 should have excellent performance.
You will want to o/c as high as you can with "reasonable" voltages and heat.

A web search using: how to overclock gtx 670 will provide links to some excellent overclocking guides.
If you look at several reviews for your video card, you will get an idea of how high your card should go.
A good starting point might be ~~The GTX 670 Overclocking Master-Guide~~ at overclock.net.
The thread has 2323 posts, so there will be many questions and answers to issues that others encountered.

Good luck with your new video card.
Let us know how everything works at stock and overclocked settings.

[tonyrowe]

Re: HELP! can i cross fire hd 6870 with hd7790

GTX 670
ok well i oc it from:
core clock: STD= 980 AFTER OC = 1110
Memory: STD= 1502 After OC = 1515
Boost: STD= 1059 After OC = 1189
that boost is not including kepla boost of 104

First 3d mark11 score:
P8221-Graphics= 9315, Physic=[ 6130 ( Was 5700 std )] phemon II X6 1100T WAS 3300 now 3900MHz

After OC =
P8595-Graphics= 10011, Physic= 6034

seems stable i didnt up to power so im not sure if i should?
GPU Temp 62c under load
CPU Temp 60c under load

[tonyrowe]

Re: HELP! can i cross fire hd 6870 with hd7790

ok i fine tuned it and im now at AS IN TECHPOWERUP GPU-Z MAX SENSOR READINGS
GPU CORE CLOCK MAX 1293.4MHZ
GPU MEMORY CLOCK MAX 1890.0MHZ
GPU TEMP MAX 66.0C
LOAD 99%
POWER VDDC 1.1750V

GRAPHIC TAB
GPU CORE CLOCK 1102.MHZ
GPU MEMORY CLOCK 1882.0MHZ
BOOST 1181MHZ
AND KEPLA when i checked 104

last 3dmark score is now p8678
Graphic 10146 physic 6087
what you think seems stable

[profJim]

Re: HELP! can i cross fire hd 6870 with hd7790

It looks like you've made excellent progress with your GTX 670 overclock.
Stress testing is good but the bottom line is if your system is stable when playing all of your games.
How is the gaming performance when gaming compared to your HD 6870?
Have you tried using higher game quality settings with your GTX 670?
You should be able to use very high game settings with your new video card where your screen display will be very smooth.

Don't forget to update your PC Specs with the brand and model number of your new GTX 670.

[tonyrowe]

Re: HELP! can i cross fire hd 6870 with hd7790

In game graphics very smooth and maxed out bf2 had extreamly good GPS even maxed out it was well over 100fps gtx 670 kicks aSs and has as high clock as 680

[profJim]

Re: HELP! can i cross fire hd 6870 with hd7790

Sounds like you're a happy camper with your GTX 670.
I assume that you meant to say FPS instead of GPS.

[profJim]

Re: HELP! can i cross fire hd 6870 with hd7790

Your average score using Human Benchmark - Reaction Time Test must be 150ms or lower for 5 consecutive tests with your high end video card.
You only have two weeks from the time you installed your video card to beat this score.
If you flunk this test, you need to return your video card and get a less powerful video card. (J/K)
Be sure to post a screen-shot of your average score for 5 or more tries.

My average score is in the 270ms range, that's why I'm stuck with my mid-range SLI video cards.
I guess this means that if I played games on my system I'd be a half-fast gamer.