Overclock.net banner

Overclocking in crossfire

1K views 19 replies 8 participants last post by  Irocing 
#1 ·
My bro and I have been debating for awhile now, the debate is whether overclocking in crossfire nets the same performance increase as overclocking with a single card. He believes that you only benefit from overclocking both cards if you are running SLI. I really want to prove him wrong but I have no AMD cards in crossfire and there are no review sites that test this. So I'm wondering if you guys could help me out. What I need is this.

Single card:
Stock clock
Bench results
Max OC
Bench Results

Crossfire-
Stock clocks
Bench Results
Max OC
Bench results

Thank you for anyone who is willing to help. :]
 
#3 ·
If I remember correctly cards in SLI will always run with identical clock speeds. So if one card is overclocked and the other is not the the faster card will be down clocked to mach the slower. If you over clock a SLI setup you need to overclock both cards to the same speed.
 
#5 ·
Well that is not entirely accurate as CF can run wit a faster and slower card and not limit the speed of the faster card. How well this works in the real world I don't know.
 
#6 ·
I know that in crossfire/SLI that the fastest card slows down to the slowest card. What I'm uncertain of is the scaling of overclocked performance in crossfire vs SLI. My bro thinks that overclocking performance in crossfire is poor versus overclocked performance in SLI. I want definitive proof to show him that he is wrong.

IE
5850 at 900mhz gets a 25% performance boost
2x 5850's in CF at 900mhz still gets that 25% performance boost versus say a GTX 460 in SLI once overclocked.
 
#11 ·
i think what OP is getting at is the debate = hypothetically OC gpu(+15% performance) + OC GPU(+15% performance) does or does not equal +30% performance in sli/cfx (correct me if im not understand your question). But as we all know, sli/cfx does not double your performance, so in a sense your brother is right. if you take the above example, you wouldnt get 30%, maybe 20% additional from OC.
 
#12 ·
Dirt 3 Benchmark Catalyst 11.6 App Profiles 11.6 CAP 3
1920x1080
Ultra Settings
8xMSAA

Single 5850 Stock Clocks
Core 765mhz
Mem 1000mhz
Avg FPS: 46.95
Fd8uN.jpg


Single 5850 Overclocked
Core 840mhz
Mem 1000mhz
Avg FPS: 50.43
pNnXf.jpg


CrossfireX 5850's Stock Clocks
Core 765mhz
Mem 1000mhz
Avg FPS: 88.45
v3wG2.jpg


CrossfireX 5850's Overclocked
Core 840mhz
Mem 1000mhz
Avg FPS: 94.29
lHZRm.jpg


Seems your brother has been proved wrong
smile.gif
The difference between the single card stock and single card oc is about 3fps whilst in the crossfire overclocking yielded an extra 6fps.
 
#13 ·
I like the question raised here. I've been wondering myself, in fact, as running quad-crossfire provides so much potential horsepower @ stock clocks..if it makes sense to further push the system considering potential heat & strain on components for what may be utterly negligible benefit. I'ma run a few tests myself here (dunno why I haven't ever before?) to see just how many "fps" are boosted in high clock relative to stock & underclocked values.
 
#14 ·
Quote:


Originally Posted by fashric
View Post

Dirt 3 Benchmark Catalyst 11.6 App Profiles 11.6 CAP 3
1920x1080
Ultra Settings
8xMSAA

Single 5850 Stock Clocks
Core 765mhz
Mem 1000mhz
Avg FPS: 46.95

Single 5850 Overclocked
Core 840mhz
Mem 1000mhz
Avg FPS: 50.43

CrossfireX 5850's Stock Clocks
Core 765mhz
Mem 1000mhz
Avg FPS: 88.45

CrossfireX 5850's Overclocked
Core 840mhz
Mem 1000mhz
Avg FPS: 94.29

Seems your brother has been proved wrong
The difference between the single card stock and single card oc is about 3fps whilst in the crossfire overclocking yielded an extra 6fps.

I'm sorry to bother you even more but can you take screens of your benchmark/s? I want definitive proof that I can show him.
 
#16 ·
Quote:


Originally Posted by fashric
View Post

Pics added


Thanks man, I use to have a 5850 myself, they were awesome cards. Hopefully he'd be satisfied with these benches. :]

Edit: Just talked with my bro, he's partially convinced but not completely, he doesn't believe the cards are OC'd enough to provide definitive data. Plus the memory is also untouched on those 5850's so that could effect part of the equation.
 
#17 ·
Well let him think what he wants its been proven that he's wrong right here. Overclocking higher isn't going to change anything and overclocking the memory yields very little extra performance so isn't really worth it and I would love for him to explain how he thinks it will have a negative impact on the performance which it would need to do if he was to be proven correct. To put it politely he's clutching at straws.
 
#19 ·
Quote:


Originally Posted by XXXfire
View Post

I like the question raised here. I've been wondering myself, in fact, as running quad-crossfire provides so much potential horsepower @ stock clocks..if it makes sense to further push the system considering potential heat & strain on components for what may be utterly negligible benefit. I'ma run a few tests myself here (dunno why I haven't ever before?) to see just how many "fps" are boosted in high clock relative to stock & underclocked values.

so ur fps went from 1000 to 1200
? damn u and ur dual 6990's! lol
 
#20 ·
Quote:
Originally Posted by tictoc;14313202
Heaven Benchmark Catalyst 11.6 App Profiles 11.6 CAP 3

Single 5770 Stock
Core 850
Memory 1200
FPS 19.8

Single 5770 OC
Core 920
Memory 1250
FPS 21

Crossfire 5770 Stock
Core 850
Memory 1200
FPS 37.5

Crossfire 5770 OC
Core 920
Memory 1250
FPS 39.6

I will up the OC to see if it scales better.
Hi,

With your 5770's, How much eye candy settings were applied in
the tests.
questionmark.gif


Later:D
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top