E13thirty7 Posted October 29, 2010 Posted October 29, 2010 I have 2 reference Sapphire Radeon HD 5870's in Crossfire, both are stock right now at 850Mhz core clock and 1GB each, i know its hard to determine how much you can OC video cards, or overclock anything, but how high could i go with my 2 5870's? I have an i7-930 @ 4.2 Mhz and 6GB DDR3 Corsair dominator GTs 2000Mhz 8-9-8-24 @ 1866Mhz 7-9-7-20, an ASUS Rampage III Extreme MoBo all in a Corsair Obsidian 800D Case, which is one of the biggest, if not the biggest, case available. Ive seen people go all the way up to 1000Mhz GPU and 1300 Memory on sapphire 5870's, but not in crossfire. Will i be able to go that high in crossfire? If not, how high do you think i can go? And, would i need liquid cooling for my cards, is it a necessity? I already have the swiftech H20-220 Ultima liquid cooling kit for my CPU.....thanks! :-) Share this post Link to post Share on other sites More sharing options...
ccokeman Posted October 29, 2010 Posted October 29, 2010 It really depends on the silicon ! The cards can be overclocked but I would suggest finding the limits of both cards and then overclocking to within 10Mhz of that edge. You will be using more current so make sure your PSU is up to the task. Water cooling does not hurt it just gets expensive with 2 full cover blocks. You can use MSI afterburner or Sapphires new overclocking utility if it is available since you can use the voltage adjustment abilities of either tool. Just because some reach 1000/1300 does not mean all, Just like with those golden CPU's that run 4.5GHz with 1.25 volts! Share this post Link to post Share on other sites More sharing options...
E13thirty7 Posted October 29, 2010 Posted October 29, 2010 It really depends on the silicon ! The cards can be overclocked but I would suggest finding the limits of both cards and then overclocking to within 10Mhz of that edge. You will be using more current so make sure your PSU is up to the task. Water cooling does not hurt it just gets expensive with 2 full cover blocks. You can use MSI afterburner or Sapphires new overclocking utility if it is available since you can use the voltage adjustment abilities of either tool. Just because some reach 1000/1300 does not mean all, Just like with those golden CPU's that run 4.5GHz with 1.25 volts! i have a 1220 watt power supple!lol. And, the reference design radeon 5870s are said to OC very well and run extremely cool...... Share this post Link to post Share on other sites More sharing options...
Hemidare Posted October 29, 2010 Posted October 29, 2010 Well just for the other side of the coin i have 2 msi gtx460's in sli and they don't OC worth a darn. I might get 800mhz core on both of them if i am lucky haven't really been trying. And they are supposed to be really good OC'ers and run cool.........but in my case i don't get much extra headroom in the OC department. Even worse my 1 gtx 460 cant OC the memory at all or i get terrible screen tearing. So like ccokeman said it depends on the silicon. You might get one of those cards to 1000mhz core but the other one doesn't OC at all. Its all about the luck of the draw. Have fun. Share this post Link to post Share on other sites More sharing options...
E13thirty7 Posted October 29, 2010 Posted October 29, 2010 Well just for the other side of the coin i have 2 msi gtx460's in sli and they don't OC worth a darn. I might get 800mhz core on both of them if i am lucky haven't really been trying. And they are supposed to be really good OC'ers and run cool.........but in my case i don't get much extra headroom in the OC department. Even worse my 1 gtx 460 cant OC the memory at all or i get terrible screen tearing. So like ccokeman said it depends on the silicon. You might get one of those cards to 1000mhz core but the other one doesn't OC at all. Its all about the luck of the draw. Have fun. so one might OC well and the other might barely OC? Share this post Link to post Share on other sites More sharing options...
Hemidare Posted October 29, 2010 Posted October 29, 2010 so one might OC well and the other might barely OC? Yes that is true. The only way to find out for sure is to take one vid card out at a time and find each ones max on its own. Then install them both and try to get as close to the lowest performing ones MHZ. So if one card does 900 mhz and the other card does 1000 mhz then you would try to clock it as close to 900 mhz for both. Hope that makes sense. Share this post Link to post Share on other sites More sharing options...
E13thirty7 Posted October 29, 2010 Posted October 29, 2010 Yes that is true. The only way to find out for sure is to take one vid card out at a time and find each ones max on its own. Then install them both and try to get as close to the lowest performing ones MHZ. So if one card does 900 mhz and the other card does 1000 mhz then you would try to clock it as close to 900 mhz for both. Hope that makes sense. no it does,lol....makes sense. Its just on the other site i belong to, overclock.net, 3/5 of every person who has the same sapphire 5870s as me in crossfire with almost identicle specs, OC'd them successfully to 1000/1300, thats what pushed me to ask this question, pure curiosity,lol. The sapphire 5870s, which is my honest opinion are the best 5870s you can buy, XFX to me cant even touch them bcuz they stopped making the reference design, there new non-reference design is locked, fail!lol. the 5870 is a very underestimated card, its -VERY- powerful, one of the best on the market, even with the new 6xxx series out, cause with my 5870s in crossfire i can run almost every game under the sun on full max settings! Share this post Link to post Share on other sites More sharing options...
GabrielT Posted October 29, 2010 Posted October 29, 2010 (edited) The thing is no one is going to brag about the one that doesn't overclock. Every card is different, all of them. Gradually take them both up and see where your limit is. Btw what power suplly are you using exactly? 1220 is an odd number, I'm just curious. If it is the Kingwin Mach 1 I would make sure each card is running on a 35amp rail and a 20 amp rail each as in. Card1 gets rail 2 and 4 and Card2 gets rail 3 and 5 or the other way around. Edited October 29, 2010 by gabrieltessin Share this post Link to post Share on other sites More sharing options...
IVIYTH0S Posted October 29, 2010 Posted October 29, 2010 Yes that is true. The only way to find out for sure is to take one vid card out at a time and find each ones max on its own. Then install them both and try to get as close to the lowest performing ones MHZ. So if one card does 900 mhz and the other card does 1000 mhz then you would try to clock it as close to 900 mhz for both. Hope that makes sense. nah that'd take too long, just overclock them together until he hits stability then back off a smidge. Share this post Link to post Share on other sites More sharing options...
E13thirty7 Posted October 29, 2010 Posted October 29, 2010 The thing is no one is going to brag about the one that doesn't overclock. Every card is different, all of them. Gradually take them both up and see where your limit is. Btw what power suplly are you using exactly? 1220 is an odd number, I'm just curious. If it is the Kingwin Mach 1 I would make sure each card is running on a 35amp rail and a 20 amp rail each as in. Card1 gets rail 2 and 4 and Card2 gets rail 3 and 5 or the other way around. yes, kingwin mach 1 1220Watt!lol....is that much power necessary? probably not. But hey, id rather have all that power and not need it than need it and not have it,lol. Share this post Link to post Share on other sites More sharing options...
Drdeath Posted October 29, 2010 Posted October 29, 2010 Also it can depend on the temps. Sometimes re-applying tim on a graphics card lowers temps as manufacturers just goop it on and lower temps on core and memory may allow a higher OC. Share this post Link to post Share on other sites More sharing options...
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