hd 4870 in crossfire help

[popjam]

i was gonna thinking of buying a hd 4890 but seen some test reviews on hd 4870 in crossfire so might get another 4870 i have a gigabyte hd 4870 1gig will i have to get the same card gigabyte version or can any 2 hd 4870 play in crossfire and does the onboard card memory have to be the same...

 

[mcalladine]

as far as i am aware it can be any other 4870 as long as its got the same ammount of memory ... but it will take both cards down to the lowest clock speed eg one is 900 mhz and one is 1000mhz they will both run at 900mhz but like i said im not 100% on this so might be best to see if any1 else says im right/wrong

 

[blaineoliver]

Exactly, they will both modulate to the same clock speed, and if one was 512mb then the 1GB would lost half its ram. This works fine, and will work a lot better than a 4890, although the 4890 would be a lot cheaper if you sold the 4870.

 

[popjam]

would i be able to crossfire with my powerpack its 650 watts, 2 six pin power cables go straight into graphic card, i only have 4 four pin molex sockets left, the adapter i got with card converts 4 pin into 6 pin and uses 2 four pin slots so I have 2 left would another adapter work to do crossfire or would I need all on main power pack??
Cheers

 

[gareth170]

Exactly, they will both modulate to the same clock speed, .

nope,

my 2 4850 doesn't... both run at they on speeds. e.g if i clock 1 to 600/1000 & other to 700/1100, both work at they on speeds.

maybe im just lucky

 

[popjam]

my motherboard can run crossfire says it will run 2 cards at x8, will that still be a lot better than a hd4890, what will be the difference from running on a x8 and a x16 board??

 

[gareth170]

my motherboard can run crossfire says it will run 2 cards at x8, will that still be a lot better than a hd4890, what will be the difference from running on a x8 and a x16 board??

what res u game at?

 

[popjam]

im wanting to play at 1280x 1028 or better with high settings on

 

[Xelene]

You don't need xfire for that resolution.

 

[jamesgoss]

I agree, the single 4870 should be more than enough for that, crossfire would be overkill in a big way

 

[gareth170]

even a 4850 would be more than enough for that res.

if u already have a 4870, why u wanna change it or go crossfire? 1280x1028 is a low res for crossfire so u won't see much different.

 

[popjam]

ok m8 wot if i wanted to play x1080 will crossfire be better or would an hd 4890 be just as good

 

[gareth170]

tbh a hd 4890 is a 4870 clocked higher, your 4870 should handle 1920x1080 fine , if u need more performance u could overclock it or get a 4870 to do crossfire.

is your 4870 not performancing the way u want it to?